With this decision having been made for me I turned my attention to the interweb to find an alternative. It didn't take me long to find out that the most economical method of building a large tank seemed to be plywood construction.
So a little bit of research later I found some plans on the net to use as a guide and set about modifying them to suit my needs. I should point out here that being a typical male I'm more into doing than planning and so while I have been pretty careful and methodical I have not attempted anything like this before and so have learnt a few hard lessons along the way.
I knew I wanted a big tank so started out by thinking about what I was going to put it on. As it happened I managed to score a very sturdy old filing cabinet/drawers from work that would be perfect for the task. It didn't have a top so I bought an off cut piece of 25mm MDF which should be more than sturdy enough.
The base and MDF top
The cabinet is 1900mm long x 500mm wide and so I figured what the hell, lets build a 2m long tank! In the interest of doing the length justice I decided to go for height as well. Little did I know what grief this was going to cause me later so I went with 800mm high planning for a water level of around 700mm. That's going to give me around 650 litres.
Following is a brief summary of the construction sequence (to date). I should point out that I did not set out with the intention of documenting the build and so some of the earlier (and probably more interesting) photos are a bit lacking. I should also point out that I have not entirely followed the conventional method/s of building a plywood tank and a lot of what you will see either comes because I happened to have particular items lying around or had free supplies.
Step 1 - Plywood Shell
The plywood shell was constructed from 21mm marine grade plywood. I didn't really need to use marine grade ply in this case but it didn't cost me any more.
Completed shell
This photo shows the completed shell. The lid is yet to be formed and is just sitting there loose in this photo. You can see that the base, ends and back are all plywood. The lid is plywood (see a little later for some more details of this). The front (which will support the glass) is a single piece of plywood with a rectangular hole in it. You don't need to build the front out of one piece (most people use timber fillets) but I had half a sheet of ply left over and it seemed like a cool idea.
All the junctions are glued with no more nails and screwed with 40mm long wood screws at 50mm crs. The heads are countersunk and will be filled and painted over later. There is no science behind this, it seemed like a reasonable amount if fixing and appears to do the trick quite nicely.
Step 2: Glass
Ok, so as you can see I neglected to take any photos, well for quite a while here actually. Ignoring the background for a minute the next step is to obtain and install the glass before you install the lid.
Glass installed
After a little bit of research on the net I figured out that I would need 16mm thick glass to provide a safety factor of 2 -3. You need to make sure you use ordinary float glass. You can use toughened glass but as it can't be cut once tempered you would have to make your tank to suit whatever piece of glass you have since the cost of tempering will likely blow the budget.
Glass thickness is all about water depth - nothing else. It doesn't (really) matter how long the tank is, water pressure increases with the square of the depth and if you make a deep tank you will need a thick piece of glass. This is where I came unstuck because 700mm deep (800mm overall) is getting really quite deep for a home tank and the cost a such a large piece of glass was out of my reach. My project stalled here for a long time while I figured this out. After a bit of further research I managed to convince myself that 10mm thick glass would be sufficient if I provided full support to all four edges - however even at 10mm thick the cost of the glass was still out of my reach. Then one day by chance I was walking past a pet store and called in and asked them if they could tell me who supplied their glass to see if I could get a better price. To my delight they did even better than that and shown me some huge pieces of 10mm glass out the back and said make an offer. I was back in business.
I had the glass cut to size by a glass company and delivered to my house. I put a strip of self adhesive foam tape (about 2mm thick x 10mm wide) along the bottom edge to even out any irregularities. I then put three strips of self adhesive draught stopping foam tape (about 5mm thick x 10mm wide) along each of the four edges. This would be used to ensure that the water pressure was evenly distributed from the glass to the plywood. I knew that the plywood would not be perfectly planar and felt that this was essential to minimise any warping of the glass.
Step 3: Waterproof Lining
This is where it all gets a bit interesting. From my observations, most plywood tanks are waterproofed using either an epoxy paint or fibreglass. A good quality epoxy paint that is suitable for potable water is quite expensive and to be honest I didn't want to go to all the trouble of filleting corners and was never really sure if I would trust it's integrity. Fibreglass didn't turn out to be much cheaper and I am still not sure if fibreglass sticks to glass so I decided against that option as well. The real reason that I was able to discard those options was because I had access to sheets of 3mm thick acrylic (Perspex) for FREE - and free is very hard to beat. Aquariums are built out of acrylic all the time and I figured this would make a perfect internal waterproofing liner.
I really didn't need to but I had a tin of black bituminous under car sealer paint left over from a car rebuild that I used to paint all the inside surfaces to the plywood for additional protection for the plywood in the event of any water sitting between the ply and the liner for any long period of time.
I then cut out rectangular sheets of acrylic, one for each of the base, ends and back and test fitted them. The corners of the sheets all overlapped nice and tight. The base and end sheets held the glass front in place and so no other fixing of the glass was required. In the end I did put in a couple of short timber fillets along the top edge to restrain it while I was moving and tipping the tank.
Now the real beauty of using a clear acrylic liner was that unlike most plywood tanks I was able to insert a background picture between the liner and the ply - nice!
IMPORTANT NOTE: Refer to the "It Leaked" section later in this article for why acrylic turned out to be a poor choice.
Step 4: Joint Sealing
Joint sealing, oh my oh my. I reckon I could write a book on sealants now but I'll cut to the chase. After having the glass and acrylic liner in it was time to seal the tank. I purchased a couple of tubes of Sellys Glass Silicone Sealant for Windows and Aquariums. I applied a generous fillet into all the corners and after a job well done waited for 7 days for it to cure.
Step 5: Lid and Top Struts
While waiting for the sealant to cure I set to work on the lid. Initially I was thinking about hinging the whole lid, but apart from this being too big and heavy and after reducing the glass thickness to 10mm thick I decided I needed to stiffen the front edge to provide support to the glass.
You can just see in the photos below that I added a 100mm wide beam made of plywood along the front edge. This serves as a longitudinal stiffener and is screwed and glued at each end and along the front. I then decided that I could use the lid to stiffen the back edge and the ends by cutting the opening portion out of the main lid. This was also screwed down (but not glued as I might want to get into the tank again one day). This made for an incredibly strong and rigid box.
View of stiffening ribs and braces
As a further (and possibly unnecessary precaution) I also decided to add three intermediate struts to further stiffen the front edge. I was paranoid about any flex in the plywood being too much for the glass and having it crack.
The trick here is to make the struts removable so that you can take them out to get large items in and out of the tank (I plan to have a large log as my centrepiece). I did this by screwing them from above so that the screws can be removed as required. At first I screwed them from the back but then realised that once the tank is against the wall I won't be able to get to them!
Transverse bracing struts
You can't really tell here but the tank is full and holding water beautifully. In the photo above you can better see the water level.... but it didn't start out that way.
Completed tank ready for water test
If you recall from above I sealed the tank and waited 7 days for it to cure. I placed the tank on the garage floor pointing towards the garage door just in case the unthinkable should happen. I filled it slowly over an hour or two and all appeared to be going well. That was until my son came yelling Dad, Dad, the tanks leaking. My heart sank to see a small puddle of water forming on the garage floor and literally as I watched it became a torrent. Something had really let go. I emptied the tank but because of the plywood and liner construction it was impossible to see where the leak was coming from (this turns out to be a significant drawback in this design) but it turns out that it was less of an issue than I first thought.
After draining and drying the tank I got inside and had a good poke around and was alarmed to find that I could peel much of the sealant away from the acrylic! This got me to thinking and after a bit of research (that admittedly I should have done before I started) I found out that silicone sealants are not suitable for sealing acrylic because acrylic is a type of plastic that exudes oils over time. This set me off on a long and painful search for a sealant that:
a) was suitable for PERMANENT immersion in water, and
b) was safe for fish, and
c) would stick to acrylic.
I searched extensively on the Internet and by talking to product manufacturers and found only one product on the planet that would stick to acrylic in a permanently immersed situation except it was not fish safe. Now don't get me wrong there are literally hundreds of products out there and the label might say that they are suitable and in a few instances even the sales reps will tell you that they are suitable but DO NOT trust anything other than the official product data sheet which will almost always violate one of the three criteria above. This is often further complicated by the fact that some products are in fact suitable for aquariums but the manufacturer does not stipulate this on the product data sheet as they do not want the liability. I'm sure that some of you will disagree and have been using various products without issue for years and if that's the case I'm glad its working for you - but I am not willing to risk 650 litres on my lounge floor.
After a little more thinking on it I realised that plain old acrylic glue could be used to join all the acrylic to acrylic junctions. To do this I tipped the tank over 45 degrees so that for each seam the sealant would pool under gravity to produce the best possible seal and provide a bit of a fillet.
Now the only remaining problem was finding something that would seal the acrylic to the glass front. Again after an exhaustive search there appeared to be nothing on earth recommended for this. Then by complete accident I stumbled upon a product called Bostik Titan Bond Plus. It's not cheap at $18 for a smallish tube but it is specifically designed for underwater use and is safe for fish and will stick to pretty much anything including acrylic. In theory you could use this to seal the whole tank but you would likely go broke in the process. I reckoned I might need at least four tubes to seal the glass but again cost meant that this was not an option. In the end I used one tube and just managed to make a very nice little seal around the three sides.
I was still pretty nervous about the seal and really wanted to add another line of defence. Again by complete chance I came across another product called Gold Label Underwater Sealer and this my friends is the greatest sealant on earth. I still don't know who makes it other than it is UK based. You can find it on Ebay and a few places in Australia sell it but no one in NZ that I am aware of. It is specifically designed for aquarium sealing and as an added bonus has almost no curing odour unlike the wretched glass sealant and is specifically suitable for acrylic. I imported a tube from the UK via Ebay and two to three weeks later sealed over all the internal joins with a nice fillet. I was now 97% sure that I was now going to have a leak free tank. After waiting the obligatory 7 days I repeated the test fill and 48 hours later called it a success and emptied the tank.
IMPORTANT NOTE: Refer to the "It Leaked" section later in this article for why acrylic glue and Gold Label turned out to be a poor choice.
Step 7: Install Plumbing
I didn't occur to me until quite late in the piece that I might need some plumbing to make all this work. I knew that I would have an external canister filter pump but hadn't quite thought about how the water would get around. I guess my initial thoughts were that I would poke the hose in through the back at one end to suck the water out and back in again through another hole at the other end. In truth this would probably have worked just fine but I had heard about these things called spray bars and water circulation and dead spots and figured I could do better.
So using the power I Google I did a bit more research and it turns out that there is some benefit to be had in having the water come in at one place and out again from another place far enough apart to generate a bit of an internal current to keep the water circulating and avoid dead spots. There are lots of ways of doing this and for my tank I chose the following.
Two holes at one end of the tank would feed the supply and return pipes from the filter pump. These holes are above water level to avoid the hassle of trying to water proof them.
Drill holes for plumbing viewed from rear.
Drill holes for plumbing viewed from interior.
For the plumbing pipework I chose 25mm uPVC pipe (common drain-layers pipe). 25mm matched the filter pump pipework in an effort to make sure that I did not restrict the water flow and hence pump flow rate. I would have dearly loved to have used clear pipe and fittings so that they would not be visible in the tank however at 10 times the price (I kid you not) I had to go with white.
Water will be introduced into the tank at the top along its full length by using a submerged spray bar just below water level. The spray bar was constructed by drilling holes along the length of the pipe. The idea here is that rather than having the spray trickle down onto the water (and being potentially quite loud and annoying in the lounge) the spray will be underwater but pointing towards the surface to cause a ripple across the surface for aeration. The water will then flow across the surface and down the glass, back across the base towards the return pipe at the bottom rear of the tank. This will cause a continuous circular flow in the tank keeping debris off the glass and directing waste towards the return pipe. The return pipe is also drilled along its length to ensure that water circulation occurs along the full length of the tank.
The final plumbing pieces are shown below.
Plumbing bits and pieces cut to length and pre assembled.
I wish I had taken some photos of all the palava I went to to make sure that the number and size of holes I drilled for the intake and return would not be too big so as to reduce the water force or too small so as to restrict the water flow to less than the pump rating. I filled the bottom half of the kids clam shell swimming pool as a reservoir. I then used our blow-up pool pump (which has the same flow rating as the pump I am going to buy) to do the pumping. The inlet hose was left in the reservoir and the outlet connected to the end of the drilled pvc pipe. I guessed holes at 50mm centres and started out with a small drill hole. I then set this up over a catch sheet so that when I started the pump all the water squirting out the holes was captured and directed to a bucket so that I could calculate the flow rate by filling the bucket in a given period of time. By slowly increasing the size of the drill holes I was able to match the inflow versus the outflow. I'm sure there are probably lots of other variables that I have not considered but I'm pretty pleased with myself for that little effort.
Completed and installed plumbing with the tank in its final resting place,
Step 8: Internal Set-up
A bit of hunting around at the local stream resulted in the find of some very nice freshwater driftwood. I have chosen a length of tree trunk as the centrepiece. It has some cool knot holes in it which I think look fantastic. I found another piece for the left hand end which I just couldn't pass up. A beautifully weathered piece of root and we purchased some river gravel for a thin layer over the bottom. I'm a bit concerned that there aren't enough hidey holes and shelter for some fish and especially the Koura so we also added some stacked rocks at the right hand end to give them somewhere to hide. In in all I think it reflects pretty nicely the natural environment for natives. Eventually I also hope to put some potted plants in there somewhere for a bit of natural greenery.
Completed landscaping
Step 9: Filter Pump
So much has happened since the initial tank setup and I have been very poor at keeping this up to date.
Koura
With the assistance of a very kind stranger with a farm at the base of the Kaimai's we collected ourselves a few Koura for the tank. Unfortunately none of these survived more than a few days. We tried again on several other occasions but in all cases they never lasted more than a few days. To this day I don't know why they did not survive and after a while we gave up trying to keep them - which was a great shame.
Ramshorn Snails
I loved having the snails in the tank but started to notice that they would find their way onto the intake pipe and get stuck over the intake drill holes. No matter how many times I removed them they would always come back and either die of starvation (because they couldn't get off) or have their innards sucked out. So after a while I gave up on trying to keep these guys as well.
As a side note, the next time we opened up the filter for its monthly clean we discovered a very large and healthy colony of snails living inside - good luck to them!
Landscaping
I have been through so many landscaping features and variations it's starting to get a bit tiresome. Almost all of the great looking roots and logs I have tried have all gone mouldy (or the underwater equivalent anyway) within a couple of weeks or months and had to be removed.
All the pre-prepared pieces at the stores are generally too small and ridiculously prohibitively expensive and I don't have a pot big enough to boil a large piece of genuine beach driftwood.
I am currently rebuilding the tank landscaping and looking for inspiration and these guys http://www.aquariumdesigngroup.com/index2.php?v=v1 have some fantastic tanks.
NZ Natives
So after deciding that I wanted to keep NZ Natives I joined www.fnzas.org.nz (Federation of New Zealand Aquatic Societies) and on the NZ Native forum discovered a woman called Stella McQueen. Stella is NZ royalty when it comes to NZ native fish knowledge and her book "The New Zealand Native Freshwater Aquarium" was a great read and an invaluable source of information.
Through the forum I meet a very kind chap who took us out for our first native catching expedition. We saw a number of eels both large and small, lots of small trout, and caught half a dozen common bullies, about a dozen smelt, a couple of beautiful torrent fish and a Koura. On following expeditions by ourselves we caught a couple of Giant Kokopu to add to the mix.
These were fed on a diet of mostly Ox heart, supplemented with meal worms, white worms, and pretty much any other live insect to was unfortunate enough to get within arms reach. The Kokopu particularly loved the occasional cockroach.
Chiller
Having endured tank water temperatures in the low 20's over much of the summer I have been very keen to get myself a chiller. With commercial aquarium chillers out of my budget and a bit of a DIY streak I thought I might be able to build my own. As usual Google proved to be very helpful in this regard and after much research I decided to give a chiller based on a dehumidifier a go.
I found myself an old Ebac dehumidifier on Trademe for $20. If you find the right kind of dehumidifier the evaporator coils in the rear (the bits you need) will be plain aluminium tubing without any attached fins (as opposed to one with copper tubing encased in aluminium fins).
My internet research revealed all sorts of relatively straight forward methods of using the dehumidifier to chill the water. Mostly these revolved around building a container of some sort around the evaporator coils and pumping the water over them. i.e.
http://www.jonolavsakvarium.com/eng_diy/chiller/chiller.html
This is all well and fine if you have the time and inclination and space but I figured I could go for something much simpler. After removing all the extraneous bits from the dehumidifier I figured if I could just immerse the evaporator coils in the water it should work just fine. The aluminium coils are very soft and easily bent so all I did was extend them sufficiently so that a decent length of them was under water. I appreciate that this is not the most aesthetically pleasing solution but it was really only intended as a feasibility test to see if sufficient cooling could be generated.
I turned the dehumidifier on at bedtime at a temp of 21.7 and woke up the next morning at 16.4 - success! Hopefully not too rapid a drop for the fish but I was not quite expecting it to work so well. Over the last week I have fine tuned the system to be on for one hour then off for an hour for a period of ten hours a day (the limit of my programmable timer) and am maintaining an average temp of around 16 degrees.
Again, the coils hanging down in the water aren't the best look but for emergency relief over summer I'm prepared to live with it. Eventually I will modify the piping to suit my needs or find some nice driftwood to disguise it all.
It Leaked!!!
With a fresh supply of Ox heart things were now pretty much back to normal and nightly feedings always a highlight. With the tepid water species previously inhabiting the tank I had not needed the chiller. I held out as long as I could but eventually decided that water temperatures were getting a little high for comfort again and re-introduced it to the tank which really did seem to perk everybody up a little.
The only drawback to this was that the Koura promptly died. I had suspected this from the first time around but now was pretty certain that the cause of this and my previous Koura deaths was the chiller. My arrangement has the aluminium coil from the duhumidifier suspended directly in the water and I believe that the aluminium was toxic to the Koura. I tried to research this on the internet a little but couldn't really come to a conclusion. So, for my tank anyway, it was either happy natives in chilled water or Koura but not both, which was a real shame. I thought later about various methods of isolating the aluminium coils from the water, which shouldn't have been too difficult, but never quite got a round to it.
So, all in all the tanks is going great and the fish seem more than happy so success all around.
May 2013
Apologies for the photos. It's really hard to photograph through glass!
Step 9: Filter Pump
Very excited. My filter pump has arrived by courier. I have purchased an Aqua One Nautilus Canister Filter CF2700UVC. This is a pressurised canister filter containing four media baskets and a UV lamp. This is going to live in the left hand end cupboard of the stand under the tank.
Aqua One Nautilus Filter CF2700UVC
Step 10: Fill and Get Filter Running
26 November 2011:
Okay, so I'm a bit nervous today. Everything is set up and ready to go, all I have to do is fill the tank and prime and fire up the filter. There is just something about having 650 litres sitting in your lounge in a tank that you built on a timber stand that I think will always make me nervous...
Update 18 Dec 2011:
The tank has been filled and running for four weeks now and all appears to be going well. We have had no leaks and the pump is performing well. Each week we have performed a 20% water change and after four weeks the filter pump was disassembled and cleaned.
I am also very pleased to report that the plumbing is working exactly as expected. The inlet pipe draws water in along the length of the bottom of the tank and the outlet pipe does the opposite at the top. This is creating some very strong circular currents within the tank which is great for avoiding dead spots and giving the fish some variety. The water from the outlet pipe ripples the surface oxygenating it and flows across the top, down the glass and then across the bottom towards the outlet pipe. You can literally watch debris cycling about.
We found that the plywood means that not much natural light gets in and it looked very dark especially with the background, driftwood and dark stones. I don't mind this too much though as it replicates the natural environment (being a natural stream with lots of tree cover and shade) very nicely, although I have installed a temporary desk lamp over the water which has made the world of difference. This will be eventually replaced with a purpose made aquarium lamp.
After the first two weeks of running with no plants and no fish we have added a couple of plants sourced from the local river and these appear to be loving the environment as they are growing profusely. We also bought a couple of cheap "suicide" goldfish from the local pet shop to help get the cycling under way and later 10 Ramshorn snails to help keep things clean. The fish seem happy and are racing about the tank so I'm guessing the cycling hasn't been too hard on them.
Update 18 Dec 2011:
The tank has been filled and running for four weeks now and all appears to be going well. We have had no leaks and the pump is performing well. Each week we have performed a 20% water change and after four weeks the filter pump was disassembled and cleaned.
I am also very pleased to report that the plumbing is working exactly as expected. The inlet pipe draws water in along the length of the bottom of the tank and the outlet pipe does the opposite at the top. This is creating some very strong circular currents within the tank which is great for avoiding dead spots and giving the fish some variety. The water from the outlet pipe ripples the surface oxygenating it and flows across the top, down the glass and then across the bottom towards the outlet pipe. You can literally watch debris cycling about.
We found that the plywood means that not much natural light gets in and it looked very dark especially with the background, driftwood and dark stones. I don't mind this too much though as it replicates the natural environment (being a natural stream with lots of tree cover and shade) very nicely, although I have installed a temporary desk lamp over the water which has made the world of difference. This will be eventually replaced with a purpose made aquarium lamp.
Planted end of tank
After the first two weeks of running with no plants and no fish we have added a couple of plants sourced from the local river and these appear to be loving the environment as they are growing profusely. We also bought a couple of cheap "suicide" goldfish from the local pet shop to help get the cycling under way and later 10 Ramshorn snails to help keep things clean. The fish seem happy and are racing about the tank so I'm guessing the cycling hasn't been too hard on them.
Bronze Comet
UPDATES
So much has happened since the initial tank setup and I have been very poor at keeping this up to date.
Koura
With the assistance of a very kind stranger with a farm at the base of the Kaimai's we collected ourselves a few Koura for the tank. Unfortunately none of these survived more than a few days. We tried again on several other occasions but in all cases they never lasted more than a few days. To this day I don't know why they did not survive and after a while we gave up trying to keep them - which was a great shame.
Ramshorn Snails
I loved having the snails in the tank but started to notice that they would find their way onto the intake pipe and get stuck over the intake drill holes. No matter how many times I removed them they would always come back and either die of starvation (because they couldn't get off) or have their innards sucked out. So after a while I gave up on trying to keep these guys as well.
As a side note, the next time we opened up the filter for its monthly clean we discovered a very large and healthy colony of snails living inside - good luck to them!
Ramshorn snail on the glass
I have been through so many landscaping features and variations it's starting to get a bit tiresome. Almost all of the great looking roots and logs I have tried have all gone mouldy (or the underwater equivalent anyway) within a couple of weeks or months and had to be removed.
All the pre-prepared pieces at the stores are generally too small and ridiculously prohibitively expensive and I don't have a pot big enough to boil a large piece of genuine beach driftwood.
I am currently rebuilding the tank landscaping and looking for inspiration and these guys http://www.aquariumdesigngroup.com/index2.php?v=v1 have some fantastic tanks.
Random pile of rocks
NZ Natives
So after deciding that I wanted to keep NZ Natives I joined www.fnzas.org.nz (Federation of New Zealand Aquatic Societies) and on the NZ Native forum discovered a woman called Stella McQueen. Stella is NZ royalty when it comes to NZ native fish knowledge and her book "The New Zealand Native Freshwater Aquarium" was a great read and an invaluable source of information.
Through the forum I meet a very kind chap who took us out for our first native catching expedition. We saw a number of eels both large and small, lots of small trout, and caught half a dozen common bullies, about a dozen smelt, a couple of beautiful torrent fish and a Koura. On following expeditions by ourselves we caught a couple of Giant Kokopu to add to the mix.
These were fed on a diet of mostly Ox heart, supplemented with meal worms, white worms, and pretty much any other live insect to was unfortunate enough to get within arms reach. The Kokopu particularly loved the occasional cockroach.
The natives thrived in the tank and after a while would feed out of our hands. However I became increasingly uneasy about the tank water temperature as natives are used to mountain streams and chillier waters.
Torrent fish
Bullies
Giant Kokopu
Chiller
Having endured tank water temperatures in the low 20's over much of the summer I have been very keen to get myself a chiller. With commercial aquarium chillers out of my budget and a bit of a DIY streak I thought I might be able to build my own. As usual Google proved to be very helpful in this regard and after much research I decided to give a chiller based on a dehumidifier a go.
I found myself an old Ebac dehumidifier on Trademe for $20. If you find the right kind of dehumidifier the evaporator coils in the rear (the bits you need) will be plain aluminium tubing without any attached fins (as opposed to one with copper tubing encased in aluminium fins).
My internet research revealed all sorts of relatively straight forward methods of using the dehumidifier to chill the water. Mostly these revolved around building a container of some sort around the evaporator coils and pumping the water over them. i.e.
http://www.jonolavsakvarium.com/eng_diy/chiller/chiller.html
This is all well and fine if you have the time and inclination and space but I figured I could go for something much simpler. After removing all the extraneous bits from the dehumidifier I figured if I could just immerse the evaporator coils in the water it should work just fine. The aluminium coils are very soft and easily bent so all I did was extend them sufficiently so that a decent length of them was under water. I appreciate that this is not the most aesthetically pleasing solution but it was really only intended as a feasibility test to see if sufficient cooling could be generated.
I turned the dehumidifier on at bedtime at a temp of 21.7 and woke up the next morning at 16.4 - success! Hopefully not too rapid a drop for the fish but I was not quite expecting it to work so well. Over the last week I have fine tuned the system to be on for one hour then off for an hour for a period of ten hours a day (the limit of my programmable timer) and am maintaining an average temp of around 16 degrees.
Again, the coils hanging down in the water aren't the best look but for emergency relief over summer I'm prepared to live with it. Eventually I will modify the piping to suit my needs or find some nice driftwood to disguise it all.
Dehumidifier sitting on top
Evaporator coils extended down into water
It Leaked!!!
By far and away the biggest hiccup to date was when the tank sprung a leak. Some five or so months after first filling the tank it started to leak. I have to admit, a day or two before I had noticed some condensation between the acrylic liner and the plywood but chose to think nothing of it. Luckily it was a very slow leak, allowing me sufficient time to dispose of the fish and empty the tank without getting more than a few drops on the carpet. I could immediately tell that this was not going to be a quick fix and opted to completely empty the tank then and there. Unfortunately for the fish, this meant that they all had to perish as I had nowhere to put them and no time to organise alternative accommodation.
I was so gutted by the failure of the tank and the loss of all the fish and hard work that I left it for a month or so while I mulled over its future. When I could face it again I started the postmortem to determine the cause of failure and this turned out to be most educational. After removing the lid bracing for access and cleaning out the interior I climbed inside with a torch and scraper. To my dismay I discovered that the Gold Label sealant pealed away from the acrylic with little resistance. I guess no matter what the claims, there really is no sealant that will stick to acrylic long term. After removing all the sealant I then discovered that the fillet of acrylic glue I placed in the corners had become brittle and hollow and was relatively easily scraped out of the joint. This should not happen with acrylic glue but I guess that it is not intended to be applied in such thicknesses. I also discovered, much to my disappointment, that the Bostick glue I used to seal the acrylic to the glass also did not adhere very well to either the acrylic or the glass with both pulling away by hand. So all in all my supposedly well researched and thought out sealing regime was a complete and total failure.
Following this I was pretty sure that there was not going to be any saving or reusing the acrylic liner and stripped it all out. Lesson learnt - don't use an acrylic liner!
The Rebuild (May 2012)
I was so gutted by the failure of the tank and the loss of all the fish and hard work that I left it for a month or so while I mulled over its future. When I could face it again I started the postmortem to determine the cause of failure and this turned out to be most educational. After removing the lid bracing for access and cleaning out the interior I climbed inside with a torch and scraper. To my dismay I discovered that the Gold Label sealant pealed away from the acrylic with little resistance. I guess no matter what the claims, there really is no sealant that will stick to acrylic long term. After removing all the sealant I then discovered that the fillet of acrylic glue I placed in the corners had become brittle and hollow and was relatively easily scraped out of the joint. This should not happen with acrylic glue but I guess that it is not intended to be applied in such thicknesses. I also discovered, much to my disappointment, that the Bostick glue I used to seal the acrylic to the glass also did not adhere very well to either the acrylic or the glass with both pulling away by hand. So all in all my supposedly well researched and thought out sealing regime was a complete and total failure.
Following this I was pretty sure that there was not going to be any saving or reusing the acrylic liner and stripped it all out. Lesson learnt - don't use an acrylic liner!
The Rebuild (May 2012)
At this point I almost gave up on the whole thing. Because I had painted the interior of the plywood surfaces with bitumastic paint, both options of going back to either epoxy paint or fiberglass linings were off the table as I had effectively ruined the bonding surface. This left my only option being some form of liner. As I had already been through all this in the initial liner selection and didn't have an alternative I thought it was game over and all I had to show for my efforts was a plywood box with a glass front. I even started thinking it might make a pretty cool coffin (for future use of course).
I researched other alternative liners including ABS, HDPE, PE etc etc and could not find anything that I was confident I could seal in this situation. Then in one final flash of inspiration (or stupidity - that is yet to be determined) I came across aluminium composite panels. I have known of these for years but it never occurred to me that these might make a suitable liner. The aluminium should be non-toxic to fish and in any event these panels come pre-painted. The aluminium and internal core is waterproof and the painted (or aluminium surface) should make a good substrate for the silicone sealant to stick to. I found myself a supplier of 3mm composite panel at a very good price and proceeded to cut up the panels just the same way as I had done for the acrylic liner.
I was still a little concerned about the ability of the silicone sealant to stick to and seal the junctions. After all this was the source of my previous failure. I did a few test samples by sealing two off cuts together at right angles, some with the plain painted surface, some with a light sanding and some sanded down to bare aluminium. After a week I pulled these apart to check the effectiveness of the bond. In truth it was a bit variable and I couldn't really decide which ones stuck best. I decided to go with a light sand as it seemed prudent.
This time around I bedded the sheets in silicone around the perimeter and again bedded the sheet junctions. I then placed a silicone bead in the corner of all the junctions. While waiting for this to cure I started to get a little nervous that my bead was a little on the small side and some more sealant was in order. This left me with yet another problem as I understand that new silicone does not stick to old. Again a test was in order and I tried two samples, one with new sealant on plain old sealant and another with new sealant on old sealant prepared by cleaning with turpentine. A week later both samples appeared to bond completely so I proceeded to use a ping pong ball to smooth a nice big fillet of sealant into all the corners.
A week later I filled the tank one quarter full and left it for a week. The following week I filled it to three quarters and re-installed the filter pump and plumbing to keep the water clean. I plan to water test it for at least a week or two before commencing re-landscaping.
Water test under way
Aluminium composite in place with protective film still on
This time around I bedded the sheets in silicone around the perimeter and again bedded the sheet junctions. I then placed a silicone bead in the corner of all the junctions. While waiting for this to cure I started to get a little nervous that my bead was a little on the small side and some more sealant was in order. This left me with yet another problem as I understand that new silicone does not stick to old. Again a test was in order and I tried two samples, one with new sealant on plain old sealant and another with new sealant on old sealant prepared by cleaning with turpentine. A week later both samples appeared to bond completely so I proceeded to use a ping pong ball to smooth a nice big fillet of sealant into all the corners.
A week later I filled the tank one quarter full and left it for a week. The following week I filled it to three quarters and re-installed the filter pump and plumbing to keep the water clean. I plan to water test it for at least a week or two before commencing re-landscaping.
I have rearranged the plumbing a little so that the intake spray bar now runs along the front of the tank. This is so that I have more scope for landscaping. With the intake along the rear I could not bank up the gravel at the rear.
After a few weeks of a successful water test, it's time to landscape and get some fish. This time I have included a false bottom to raise up the level of the gravel for better visual effect without having to add deeper gravel and weight. I decided to go with a smallish sized natural gravel that contains a variety of colour. Also this time around I splashed out and bought some nice schist rocks. These have great grain and in conjunction with a centrepiece of driftwood and a few plants I am very pleased with the result.
After a few weeks of a successful water test, it's time to landscape and get some fish. This time I have included a false bottom to raise up the level of the gravel for better visual effect without having to add deeper gravel and weight. I decided to go with a smallish sized natural gravel that contains a variety of colour. Also this time around I splashed out and bought some nice schist rocks. These have great grain and in conjunction with a centrepiece of driftwood and a few plants I am very pleased with the result.
As I don't want to heat the tank I am rather limited in the type of fish available. I am not that keen on gold fish and particularly because of the enormous amount of waste these guys generate. I was hoping to try sub-tropical (tepid) water species but have been monitoring the temperature over the winter months and even indoors the temperature is getting as low as 16 degrees which is a bit chilly for most. For the time being then I have decided to give non-goldfish cold water species a try. Around here that is really only white or gold Mountain Minnows, Leopard Fish and Butterfly Suckers. Over summer I consider introducing Paradise Fish and Guppies to acclimatise.
So far I have had a handful of Mountain Minnows and a couple of Leopard Fish in the tank for about a month and just noticed the other day 3 or 4 tiny babies so everyone must be happy!
December 2012
Well I have given the tepid water species a go for a while now but I have decided to go back to natives. The tepid water species are extremely dull in behaviour by comparison so I can't wait to get some excitement back in the tank. For the time being I will leave them in there with the natives so that might be interesting!
We visited a local stream a couple of weekends ago. The water quality appeared pretty good but I was surprised to find very little life. There were a few smelt present and we spotted a few nice sized Kokopu and Koura but little else. We kept a few smelt and a great looking Koura. We haven't had much luck with Koura surviving captivity before but I am pleased to say he (or she?) is doing well. He is eating peas and ox heart and spending more time out of hiding during the day already.
These are a couple of pictures of him trying the big escape and generally wandering about.
A few weeks later, a late night trip to our favourite back country stream provided the final stocks for the tank. We managed a good selection of smelt, bullies, Inanga and a couple of beautiful Torrent Fish.
With a fresh supply of Ox heart things were now pretty much back to normal and nightly feedings always a highlight. With the tepid water species previously inhabiting the tank I had not needed the chiller. I held out as long as I could but eventually decided that water temperatures were getting a little high for comfort again and re-introduced it to the tank which really did seem to perk everybody up a little.
May 2013
A sad day I have to report. We are shifting rental houses and I have decided to sell the aquarium. Yes I know I could move it, but to be honest moving a four bedroom family with all of our associated junk is difficult enough already without the added hassle of trying to keep the fish alive in the process and I can't really be bothered. While I love the natives and am very proud of the finished aquarium a lot of the thrill was in building the tank and now it's time to move on...
February 2014
Just for fun - I recently came across a chap called Jack Heathcote who has what may be the largest privately owned freshwater aquarium in Britain.
Check it out here http://www.practicalfishkeeping.co.uk/content.php?sid=2951
Unfortunately I have more recently heard, that due to the prohibitive and skyrocketing electricity costs of heating and filtration, that he will be rehousing his fish and down scaling or closing this tank which is a great shame.
Update here http://www.practicalfishkeeping.co.uk/content.php?sid=6208
Now there's some inspiration for a new project!
February 2014
Just for fun - I recently came across a chap called Jack Heathcote who has what may be the largest privately owned freshwater aquarium in Britain.
Check it out here http://www.practicalfishkeeping.co.uk/content.php?sid=2951
Unfortunately I have more recently heard, that due to the prohibitive and skyrocketing electricity costs of heating and filtration, that he will be rehousing his fish and down scaling or closing this tank which is a great shame.
Update here http://www.practicalfishkeeping.co.uk/content.php?sid=6208
Now there's some inspiration for a new project!
August 2021
Check out my new monster build here
