Custom tank construction

I've been reading a lot of threads around the web, especially on Monster Fish Keepers, on the topic of building a custom tank. In a couple years I'll have a house again where I'll be able to think about making a large aquarium a permanent fixture of a garage or basement. I was planning on something around a thousand gallons, partly based on the dimensions of standard plywood.

I'm wondering if there's a reason for lumber and plywood being the material of choice for DIY tank builders. It seems like it would be difficult to seal and even more difficult to deal with a leak. I was considering brick or similar masonry, or having a metal box welded by a shop, in either case sealing the inside with the usual fish-safe epoxy. Metal seems like it could be pretty cheap, since you wouldn't need much as far as specifications - "weld these sheets together in a box and put some angle iron around the top and window" should be sufficient.

Has anyone ever heard of a home tank that was built with materials other than wood?

I'm wondering if there's a reason for lumber and plywood being the material of choice for DIY tank builders. It seems like it would be difficult to seal and even more difficult to deal with a leak.

The reason why people use wood is because it's cheap, easy, and no it doesn't leak. Here is an example of a 237 gallon tank and stand built out of plywood for $375:
http://www.youtube.com/watch?v=cdyANDq_x_s
That's $1.58/gallon.

Edited by EricaWieser, 03 March 2013 - 07:37 PM.

I used high quality plywood, AC, or BC. Has a finished veneer, and no knot holes. 3/4 inch plywood can be glued, and screwed, and does not need additional structural framing. It is relatively cheap. I taped the seams with wide fiberglass, and applied several coats of fiberglass resin from home depot. DO IT OUTSIDE, if you want to retain most of your cognitive abilities. Worked great. I let it cure a couple weeks, washed it, filled it for several days, then drained it. Then I set it up. Pay attention to glass thickness recommendations, as the taller the tank, the more pressure on the glass. I used hardware store 3/4 aluminum L angle around the top, and a couple of flat aluminum braces across the top. You can screw these together. I used slate tile, and fastened that to the rear wall with pure silicone, made for a pretty nice natural look.

Here is the play by play. http://forum.nanfa.o...k stream tank

My understanding has been that anything around 200 gallons and under, it's more economical to buy it.
Unless you want an unusual design or have access to the glass already.
With Craigslist, etc, you can sometimes get some good deals. It depends upon your area and what you
have access to. I bought my 210 for 300 dollars. Around here, I couldn't buy the glass for that price.

I cruise through this place( http://giantaquarium.wordpress.com/) every so often, just to see what's listed.
They show 300 gallon plus tanks on craigslist from the whole country. This is the new location, so the listings only go back so far.
I've seen some really nice tanks, but few from my area. There were a couple big ones(800+) close to me sometime last year,
but they got sold out from under me.

If you're going to custom build a 1000 plus, it would likely be lower cost.
I think that it depends upon what materials you have access to and your skills.
I remember seeing some arapaima, shark, reef, etc setups that were built using concrete blocks with a large viewing window over the years.
Most of them were on MFK or they at least linked to them.
I still drool over the thought of using a heavily modified steel shipping container with huge windows.
Even though I have several of them, it's the windows that run up the price.

Scott

Blocks, and brick are more difficult to seal than plywood. May seem odd, but it is the case with tanks.

A guy in our club built a 1000 gallon tank in his basement. Below is a link to the article about it. He hosted us all one night and gave a great talk. He now lives in Miami. He built several of them over the years.

Several points..

1, He said the tank did not add to the value of his house. He built his out of concrete.
2, It is really really heavy so it pretty much has to sit on the concrete foundation.
3, The water source has to be near the tank. He plumbed it right to the tank.
4, The tank has to have a drain so it can drain completely and there has to be enough head room to reach in it. That drain should be has close or on a drain has possible. He also kept the room barefloored. The drain needs to be big has well so it can drain fairly quickly and not clog.
5, He put the rocks and the logs in before putting in the windows, He did it the other way for his first tank and it did not work has well. It also takes a lot of rocks to make it look right. He cemented in some of the base rocks to make sure they would not fall over into the windows. None of it leaked but I do not remember how he sealed it.
6, Lighting has be just has big has the tank if you want plants to grow. He used metal halides. The electricity for it was significant for the heaters and lights so the wiring had to be planned along with the weight and water.

7, He used several large heaters to heat it rather than one huge heater.

8, Think carefully about what goes in the tank has it is very difficult to get a particular fish out. He used fish traps to remove the many baby fish that the tank produced. He also had trouble with a few of his fish hybridizing after he had been told that some related fish would not. They did anyway.

9) He built his first tank himself and found it a lot of heavy work. He used a contractor to do the heavy work for the last tank, but it was built to his design.

10) He loved his huge tank but it did cost more than he thought and it was expensive to run. I do not believe it had a filter I believe he just used water changes. He had a mark on the tank to drain the water to every week and then he had a valve on the inlet water that woud shut off after it pumped in so many gallons of water. I believe it was two hundred gallons. Depending on where you live that water and sewage cost can become a significant cost.



http://www.cichlidga...cles&Itemid=112

10) He loved his huge tank but it did cost more than he thought and it was expensive to run. I do not believe it had a filter I believe he just used water changes. He had a mark on the tank to drain the water to every week and then he had a valve on the inlet water that woud shut off after it pumped in so many gallons of water. I believe it was two hundred gallons. Depending on where you live that water and sewage cost can become a significant cost.

A Walstad style setup would solve that problem. In her book Ecology of the Planted Aquarium, Diana Walstad describes how she used live plants to reduce the frequency of water changes to like once or twice a year.

Plant growth can be crucial to large or expensive setups. My 150 gallons of saltwater would cost a $50 bucket of marine salt for every full water change, which at 25% a week would be $50 a month. But almost a year since setup, nitrate is still between 0 and 20 ppm (the lowest my test kit reads; it's cheap) and I've never, ever done a water change. Ditto all my freshwater tanks, which it's not necessarily expensive to do water changes, but let's be honest it's just easier not to have do. I do a water change in my freshwater tanks like....every few months. Nitrate's constantly 0-20 ppm, no matter how long I wait in between water changes.

Yeah, the Walstad concept is crucial for large tanks. A 25% water change doesn't seem like a big deal on a 10 gallon tank, but on a 300 gallon tank it's way less fun to do every week.

Edited by EricaWieser, 04 March 2013 - 05:53 PM.

6, Lighting has be just has big has the tank if you want plants to grow. He used metal halides. The electricity for it was significant for the heaters and lights so the wiring had to be planned along with the weight and water.

Personally I would have used full spectrum fluorescent bulbs or LEDs. Metal halides are very very expensive and don't really offer much of an advantage. Here, I'll explain.

Here's a nice graph that you can see the efficiency of the number of lumens (units of light brightness) per number of watts (units of energy consumed; what you have to pay for):
http://www.ledrunlights.com/lChart.gif
From source webpage: http://www.ledrunlig.../ledlights.html
Incandescents give less than 20 lumens per watt
Fluorescents give less than 60 lumens per watt
LEDs give less than 90 lumens per watt
This source says that metal halides give between 65-115 lumens per watt: http://www.ventureli...-techintro.html
so metal halides range from the same brightness per watt as a fluorescent to the same brightness per watt of an LED (almost twice that of a fluorescent bulb).

But now let's talk about price. The following are three very competitively priced products from the best aquarium lighting website I know of at the moment, aquatraders.
The fluorescent light is 215 watts and 20,000 lumens, and $110: http://www.aquatrade...ure-p/52325.htm
The LED light is 1 watt and 4900 lumens, and $150: http://www.aquatrade...-TR-p/56275.htm
The metal halide light is $300: http://www.aquatrade...mbo-p/54267.htm
It is 750 watts. I couldn't find the lumens but I'd imagine they'd be like 50,000 to 85,000 based upon the previous efficiency conversions.

A fourth lighting option for big tanks that comes from a different vendor is a $10 32 watt T8 fixture with bulbs for $9.
A $20 total light fixture is very appealing, especially when you consider that a 'good' aquarist changes their bulbs every six months. (I look at my T5HO which would cost $80 to replace the light bulbs and make a sad face).

Those T8 full spectrum bulbs work great to grow plants. I own four on various tanks. The fixture looks like this: http://www.homedepot...ml#.UTUngDC-2uI and is $20 from Home Depot or $10 from Walmart. It is a 32 watt T8 light fixture that is four feet long. The bulbs look like this: http://www.homedepot...ml#.UTUnrDC-2uI They're 6500 K ( a little bit yellow looking; some people like their light more blue) so you can have these as the majority of the lighting in your tank and then put a bluer looking 10,000K or actinic near the viewing pane. The overall tank looks blue if you do it that way, and you save money. Here's a picture of my tank with the $100 T5HO near the front viewing window and the $20 T8 towards the back: http://img.photobuck...imiru/004-7.jpg If your tank was three feet front to back that'd save you money. The power draw from a 32 watt T8 light fixture is quite insignificant. The Daylight Deluxe T8 bulbs are 5500 lumens per fixture for 32 watts total. Yes, the LED uses less watts, but despite Usil's best efforts I still haven't figured out how to build an LED fixture for $20.

In my personal experience, I have found that limiting the light in the aquarium to only 100 lumens per gallon is best. Above that and the algae growth is ridiculously fast. You can support some straaaange life forms with more than 100 lumens per gallon. I had cladophora algae as a ground cover one time. True story:
http://img.photobuck...kiimiru/019.jpg
http://img.photobuck...imiru/058-1.jpg

*shrugs* There are a lot of different ways to light big tanks. Metal halides are certainly one way to go. Multiple smaller lamps work too. I have found that multiple small lamps is what I prefer, but it turns out there's really no wrong way to do it, except to buy something without fully knowing what the alternatives would be. When you're outfitting a big tank, not thoroughly researching your options can cost you quite a lot of money.

Edited by EricaWieser, 04 March 2013 - 06:49 PM.

Erica, the problem is with space. With metal halide you can get 400 watts out of 4 square feet of space. A florescent fixture yields what 160 watts per 8 square feet. Can only fit so many lights above a tank. So really you are wrong. Metal halides are the best choice for lighting a tank that is large, and deep.

I dont think anyone mentioned it but another reason people use plywood rather then block is that its not permanent. incase you move, fall into bad times. a wooden tank is easier to move or discard then block/cement tanks.

I'm sure wood is reliable for smaller construction, but nobody on MFK has heard of a wood tank > 3 feet deep that was leak free, and I'd kind of like the depth. Partly I'd like the height to be sure kids can't fall in, but also I'd like to be able to use the depth for features like a big tree stump or something.

Does anyone have any thoughts on the metal option? A wood tank could be disassembled, but a metal tank could be moved relatively readily, plumbed more reliably, and is probably cheaper.

Erica, the problem is with space. With metal halide you can get 400 watts out of 4 square feet of space. A florescent fixture yields what 160 watts per 8 square feet. Can only fit so many lights above a tank. So really you are wrong. Metal halides are the best choice for lighting a tank that is large, and deep.

Old news! .An LED fixture can put a lot more light into a small deep area than a metal halide. I have a 47 gal column tank with dimensions of 20"L x 18" W x 30"H set up as a coral reef. The initial lighting system was a single 150W HQI metal halide, and currently I'm running a 120W LED fixture on the tank. The LEDs are running at about 33% of their max output and the tank is noticeably brighter to the eye. It should be noted that when LEDs and halides are producing equal PAR numbers, halides appear brighter to the eye.

I'm sure wood is reliable for smaller construction, but nobody on MFK has heard of a wood tank > 3 feet deep that was leak free, and I'd kind of like the depth. Partly I'd like the height to be sure kids can't fall in, but also I'd like to be able to use the depth for features like a big tree stump or something.

Depth of the tank is the #1 factor in thickness of glass (and cost of tank). Unless you have a specific reason to prefer extremely deep tanks, I'd avoid them for cost reasons alone. Here is a glass thickness chart: http://www.livingree...ors-t21048.html
If you go price those thicknesses out you'll see that the cost isn't linear. The thicker glass is exorbitantly more expensive.

"Does anyone have any thoughts on the metal option?"

I still have fantasies of using a 20 ft to 40 ft shipping container!
Again, for me, the biggest obstacle is the cost of the glass, acrylic or whatever.
A few years ago, I tried to talk my local sanitation company out of one of their 20 ft dumpsters.
They weren't amused!

I'm sure wood is reliable for smaller construction, but nobody on MFK has heard of a wood tank > 3 feet deep that was leak free, and I'd kind of like the depth. Partly I'd like the height to be sure kids can't fall in, but also I'd like to be able to use the depth for features like a big tree stump or something.

Does anyone have any thoughts on the metal option? A wood tank could be disassembled, but a metal tank could be moved relatively readily, plumbed more reliably, and is probably cheaper.

No reason that you couldn't weld up a box similar to building one out of wood. The epoxy paint that's used to seal the plywood was actually developed to coat the inside of metal water storage tanks so no issues there. I don't know where you'd get the info on necessary thickness of the metal, which to my mind would be critical because of the weight.

I don't think info on metal thickness will be hard to come by. I think I would have it ribbed with angle iron too, around the top and windows.

Depth is mostly about the kind of features you can have (I want a sunken log and tree stump). The window doesn't necessarily have to go all the way to the bottom, but also I don't necessarily mind paying for good glass or acrylic. I have looked at those prices.