crazy?

[bobberwobber]

hey again...
ok... this may be a crazy idea... i dont know.. i was just browsing around and stumbled across a forum post, cant remember which forum it was now... but guy wanted to know if he could join 2 55gallon tanks together... i had thought of this, as i wanted an 8foot tank, for my balas, but after looking into it, the amount of engineering and structure required, not worth it...
but he actually wanted to make it, 4x4... using the long sides to make a large square tank, so be 4x4x20 or so.. 240gals, give or take...
hmmmm... i dont think the glass of a 55gal is thick enough to support that.. the calculators say it is, as obviously the actual surface area on the glass is the same but still... but i then realised, i have a 75gallon, sitting in pieces in the basement, which i was rebuilding.. this has nice thick 10mm glass and is 4 foot... so, i was thinking, if i could source another cheap.. thick this one cost me $15.. and then used the 4foot sides to make a large square tank.
base would be plywood (calm down, hear me out lol).. plywood, fiberglass reinforced.. im a boat designer by qualification, so my thinking is, id just do a plywood sandwhich fiberglass base, be plenty strong enough, probably overkill but still.. then use a thin sheet of glass over top, basically, just to avoid risks of osmosis etc and give silicone a better grip.. i figure, the base, doesnt matter what it looks like, you cant see it, long as it strong enough, and a 8square foot piece of 10mm glass is going to probably cost the same as a new tank lol...
anyway.. id like to put it in the basement, so it on a solid concrete floor, as dont think living room will support 2000lbs in the middle....probably make some form of custom top and bottom frame, using fiberglass with unidirectional mat or maybe plywood sandwhich again, so doesnt flex and bow.. probably keep top open and hang lights over or make a canopy of some sorts.. but we were just looking at the idea and have the space, have the materials... thinking that would make a great Ray tank... always wanted a sting ray or something along those lines but know they need big tanks... utilize one of the 55gals i have laying around as a sump filter and drill the new tank etc etc..
any input? am i just living in la la land, or think it doable?
also, am i right in thinking this be a great ray tank?

probably wont happen for a while.. still got to finish off the wall tank.. work using up my time lately.. but tossing the idea around so wanted some input...any issues im missing pointing out etc...

 

[mfdrookie516]

i can tell you that two 55g tanks dont make 240g... 55's are 13" wide which would make it just over 2'x4'... the main problem i would have with a tank that is 8'x13" would be that it would be incredibly unstable because of the lack of width and realistically, wouldnt be much better for balas as they need more room to turn around than that... just my opinion though and maybe i misunderstood your post a bit

 

[bobberwobber]

yeah 2 55s, would be 110 and no way putting 2 end to end would work, you would have a very bad weak spot bang in the middle... what i was talking about was the 75gals, using the long sides of 2 tanks, to make a 4x4. throwing away the end pieces.

 

[BigJim]

I think I get what you're aiming for.

First, the water pressure and the requisite glass thickness depend on the depth of the water, not the volume. A 10g tank that's a foot deep and a 1,000,000g tank that's a foot deep need the same glass thickness to handle the pressure. It's the fish hitting the glass that is usually the reason to up the glass thickness on a larger tank.

Second, plywood is commonly used to build large aquariums. Glass is really expensive, so people build huge plywood boxes with a few glass windows/sides and seal the wood with fiberglass or another resin. It seems to work well. Google plywood aquarium and start researching.

Third, really think out your frame design. The plastic frame on 55g and 75g tank is structural. I've seen 55g tanks crack and fail if even the center brace is removed. You can get away without a frame, but you have to use thicker glass.

Fourth, you'll still have to build a stand of some kind to level out the tank. Your basement floor should slope towards the drains and big tanks are prone to failure if they're not level.

I think your 4'x4' mini-pond would be great for a sting ray. If you plan it out well, I think it's very doable.

 

[bobberwobber]

bigjim.. thanks...
i figured the glass thickness was more about surface area than it was actual volume behind it. larger tank, loads are spread over larger area anyway.. so yeah, im thinking the 10mm glass be plenty big enough... i may even use the 55gals... ill see...
the frame i have thought about.. i will probably do wood. using 2x2s and then router out a groove down the middle, which the glass slots into. i will probably resin coat them, top and bottom, so wood doesnt get damaged from spray and water changes etc... incorporate cross braces into it. i will probably also take 2x2s, run them over a table saw to cut out the middle section, and then put them upright in the corners.
think the final idea we have is to make it almost like a gazebo in the basement, with a roof over it, and then just netting over the top of tank, so cats dont get in and balas dont practive flying.... hang the lights in the roof... im confident the frame and so forth will be plenty big enough.

i design and build boats, so i figure, same thing, just keeping water in, not out like a boat lol.. i have built a couple fishponds out of fiberglass which are still running leak free after 8 years so be ok there.

we not going salt with it.. id love a ray but cant afford to invest that much money into another salt. rocks, protein skimmers etc. its just too much money so it will be for the bala sharks... maybe get a couple more...

thanks for help... ill have to sit down with autocad and see what can whip up....future project once salt done..

 

[BigJim]

There are freshwater rays. I believe all the rays I've seen in aquariums have been freshwater. Just thought I'd throw that out to cause some trouble.

 

[Kungpaoshizi]

Why not cut a big circle in the glass on each end of the tank, and then seal a big pvc pipe between the two sitting next to each other?

Just big enough for the fish mainly, too big a hole would equate to a severe loss of structural integrity on the ends...

 

[jessibell]

I love those big tanks they have at some Petlands - they're probably 4' by 4' but only a foot high. They are riased about waist high so you can look in from the sides and from the top.

The plywood tank is a fantastic idea. I had no idea that could be done!