Consensus on plywood tanks?

[npaden]

Well, I've been reading through a bunch of old threads on plywood tanks and haven't been able to reach a conclusion. I'm looking at a 8'x4'x3' tall refugium. No viewing panes needed. I was going to build the walls much like you would a wall for a house out of 2x4s and then put plywood in the inside. I would be able to insulate it with regular insulation that way as well as it would be in an outdoor shed.

I was originally planning on just going with a pond liner but reading through the threads there were concerns with leaking and especially with water getting between the liner and the wood and rotting it out.

Some other common plans are 2 part epoxy and some have used a PVC sheeting material with silicone in the corners.

I am looking for something that isn't super labor intensive and not to expensive. I would just go with the 300 gallon rubbermaid stock tanks but they are such a crappy shape I could build a 3' tall 2,700 gallon plywood tank in the same space 2 of the 300 gallon rubbermaids take up!

Anyone have a good suggestion for me?

Thanks, Nathan

 

[taikonaut]

Why don't you stack a bunch of the rubbermaid tanks on top of each others as if you put them away for storage....

Sorry, not that funny, I guess. If you don't need a view panel, it is much easier to build. Depends on it intended use, pond liner should be sufficient unless you bang rock/skeleton/sharp objects on it very often.

Unfortunately, there is no much data when it comes to DIY plywood tanks.... just try to find data on glass/acrylic tank, and there is no much out there! Certainly the skill of the DIYer plays an important part, but for better reliability, you may want to use a combo method, for example, wood frame with epoxy *and* pond liner.

When it comes to cost and labor, nothing beat pond liner, but for durability, you need to go a step further. Custom-made premolded fiberglass tank is the opposite of pond liner, so go somewhere in between.

 

[hdtran]

Robert Metelsky, in his "Simplified Reefkeeping" book, describes how to build plywood tanks with a glass viewing panel. Since you're avoiding the glass viewing panel, it should be a lot easier.

What is going to be more difficult is the 3' height of the refugium/sump. This height (and the 8' length) will generate a lot of pressure on the plywood. You'll need lots of 2x4's to brace the plywood to withstand the hydrostatic pressure.

I think Taikonaut's suggestion of belts and suspenders (marine epoxy paint on the plywood and a pond liner) is excellent. A vynil (vinyl?) liner, as in swimming pool liner, might not be an expensive alternative to pond liner. In fact, come to think of it, I wonder if you could find an above-ground wading pool (3' deep is quite feasible) as an alternative construction.

 

[npaden]

I was planning on building the frame for the plywood with 2x4's on 16" centers just like a wall. Then I was going to put insulation on it like a wall. I was going to use a 3/4" sheet of plywood on the bottom to keep the bottom from expanding out and use 2x4 or 2x6 braces across the top for the same purpose.

How much time and effort would it be to put the marine epoxy paint? I would probably just do the whole thing with epoxy and forget the liner if I was going to do it that way.

Thanks for the ideas, Nathan

 

[Fl_Seagull]

Did you look at this guy's idea?
http://www.aquariacentral.com/diy/pond1.shtml

 

[Fl_Seagull]

Epoxy paint is wonderfull stuff.

But it is a pain to work with.

It runs easily if you don't let it sit of a few minutes before using. But, the time it needs to sit varies with how much is mixed and the outside temperature :? . If you haven't works with it before it can be frustrating. Sure you can sand it. But, it will gum up the sand paper if you try to start sanding too quickly. Cure time is very temperature related. I have had it cure in 23 hrs or had to wait longer than 48 hrs. If you're putting on 4 coats(the recommend number of coats), you could easily take more than a week to just paint. Don't think about paint inside your house unless your living somewhere else. Thus, you're painting outside with all the leaves, grass clipping, bugs... :evil: ....

Of course, you can get all done only to discover the plywood has some hidden defect which results in you tank leaking :roll: .

I would look at your costs. You may find epoxy paint is not the cheapest or best option for you. Your empty tank will be very hard to move. If you have to paint it in your living area (and I include basement), I would not recommend using it.

 

[taikonaut]

I don't know how easy it is to get, but I have seem some fiberglass panel that you can bolt together with SS316 or titanium bolt and make into a water-proof tank... maybe out of range when it come to cost if you are not public aquarium, but it is very portable since everything is 4X8 feet when disassembled....

 

[npaden]

Fl_seagull,

Thanks for the link. That is what I am leaning toward. With the 2x4 frame and the plywood inside you can make a very sturdy tank and if you lap the lining over the top of the frame you shouldn't have anything spilling down between the frame and the liner.

I also like the fact that I could insulate it really well that way as it will be in a shed.

I could even cover it with a insulated cover on really cold nights to keep even more heat in.

I'm still open to other suggestions though.

Thanks, Nathan

 

[Sprattoo]

What about a cement?
If it's going to be outside weights not an issue. Maybe a pool company would give you a good deal on something so small?

Just a thought.

 

[npaden]

Well, I think I have found my solution!!!

The local ag place here makes irrigation water storage tanks. They have a top with a 16" manhole at the top. They make one that is 7.25' in diameter and 4.5" tall. I could bury it a few feet in the ground and cut the top open and leave a rim about 3 or 4 inches around it for structural support. If it ends up seeming to flimsy I could put a strap around it as well. It is $397 and holds 1,225 gallons!

I drew a layout for the shed with it in there and it looks like a pretty nice layout.

Thanks for the help! I don't think we figured out anything on plywood tanks but I have my answer!

Thanks again, Nathan

 

[FranklinP]

Garf has some good plywood info.

Last summer I made a pool for the kids out of PVC frame and a large farm tarp. I ended up having to place a cable with two loops on ends around the rim of the pool, then I inserted a pipe into the loops and began to twist it until tight. This braced the top frame against the outward force of the water. SO my thought is to run this cable system around the top of your ag tank to help keep it round and to strengthen it. Good luck.

 

[Sprattoo]

what kind of aquaria requires..... 1500 gallons of refugium?

Are you just going to mass produce Corals or LR, Live Sand? Is it going to be lit? Is this for your own pet shop?

I'm just curious 1200 - 1500 Gallons is quite a slice of ocean. I'm also curious if you have a plan to get to whatever is in the center?

When I finally buy my life time house I will be setting up something this in my basement I am sure of it..... An open tank to grow rocks, breed Coral or whatever, to supply local hobbyist that would like to chose not to get ripped off.

 

[npaden]

what kind of aquaria requires..... 1500 gallons of refugium?

I actually was only looking for a 600 - 800 gallon size but still haven't found one with good dimensions. I just tend to overstock my 415 and have always had some minor algae problems. My thoughts are that adding another 1,000 gallons of water with a very low bioload will help this. I thought about the problem with not being able to get to the center but I just wouldn't put anything in the center.

I will probably end up with racks of some kind around the perimeter where I can frag or propagate stuff. I had originally thought I could throw a clown pair in there but I could always add on a few small tanks with a couple pairs of breeding clowns if I needed to.

The roof is basically the only remaining item that needs to be resolved. I haven't decided exactly what type of greenhouse material to use or whether to just build a regular roof with skylights.

FWIW, Nathan

 

[taikonaut]

>.. I thought about the problem with not being able to get to the center ...

Get one of those pair of rubber pants that fisherman use to get into water.... unless you are shorter than 4.5feet, I don't see any problem.