538 gallon tank

KoiKeeper

Feeder Fish
MFK Member
Jan 4, 2015
5
0
0
KY
Hi, this is my first time building a tank and I have some experience with carpentry and plumbing. All measurements are in US inches and gallons unless otherwise specified. I prefer to find as much of the products in stores rather than online so I can inspect the quality and less hassle with returns if needed.
The Tank
Phase 1: Building the plywood box
I plan on using (2) 96" x 36" Whole Piece Birch Domestic Plywood from Homedepot for the front and back,
and the same type of wood for the (2) 36"x 36" sides and (1) 96"x 36" bottom. Then screw in #8 2-1/2 in. Phillips Square Flat-Head Multi-Material Screws every 6" apart and glue the sides with Gorilla Glue 2 fl. oz. All-Purpose Adhesive.


Phase 2: Liquid Rubber
I plan on using 5 gallons of Universal Rubberizeit and 2 small rolls RubberizeIt!™ ReinforceIt™ Cloth for the sides and glass.


Phase 3: Cutting the side for the glass
Cutting the front panel for the glass (I'm going to go with glass, not acrylic because I want this to last for a very long time without scratches and yellowing) I don't know how thick the glass should be. I heard 1/2" thick 92.5" x 32.5" safety glass with rounded edges is sufficient. If I stick with the 92.5" x 32.5" for the glass, how much room should I leave to use silicone adhesive? What type of silicone should I use? I heard the mildew resistant kind is toxic over time and the aquarium silicone is the same as the silicone without mildew resistance, but more expensive.

Phase 4: Bracing and stand
2x4 boards for every foot for the bottom, the top and the sides. I'm going to reinforce the bottom with the remaining amount of plywood since Homedepot uses 4'x8's. For the stand I'm just going to use cinder blocks and then cover it up with some thin pieces of plywood. I'll be painting everything once I know it works.

Phase 5: Testing
I'll fill up the tank halfway with water for about a 5 days to see if they'res any leaks and then fill it up all the way for 5 days before I put anything into the water.

Phase 6: Filtration (Haven't done enough research for this part yet)
 

muttley000

Gambusia
MFK Member
Nov 24, 2011
304
1
18
West Unity, OH
This sounds awesome. That's a lot of tank for those 3 fish! I'll give my opinion on some of your points.

I would double up the screws and make sure you predill properly.

I personally wouldn't use liquid rubber, I'm an epoxy guy. There are plenty of successful builds out there that use it.

I would be worried at 3/4 thick glass at that size, and would use 1" to get a higher safety factor. Going a little shorter would help a lot. At 24" tall you could go down to the 1/2" IMO.

Any silicone is supposedly fine as long as you let it cure fully, but I would look at a silicone made to be used as an adhesive like the RTV line by momentive. There's always a debate about the mildew inhibitors, and stories of success when used, why risk it IMO.

If your using 2x4s under the tank I would guess you are looking for trouble. That is going to be over 2 tons, I would go with 2x10's under it every foot. How are you planning on bracing the top?

Good luck, looking forward to seeing your project
 

KoiKeeper

Feeder Fish
MFK Member
Jan 4, 2015
5
0
0
KY
Update:

Looking for cheaper places on wood and glass.

Going to change from Rubberizeit to Pond shield (3) of 1.5 quarts, so I can make 20 mil thickness instead of 10. Fiber glassing the joints then applying the pond shield over it and adding silicone.
 

paulW

Plecostomus
MFK Member
Jun 12, 2008
525
83
61
ohio
I have never built a plywood tank before.. but wouldn't 3/4" plywood used in subflooring be cheaper? I know it would be stronger than plywood designed for cabinents furniture (like the birch you are looking at).. I don't know if strength difference significant, and I don't know if you can even use it for a plywood tank, but just an idea to save some money.
 

KoiKeeper

Feeder Fish
MFK Member
Jan 4, 2015
5
0
0
KY
Ugh never mind. More cost effective to buy Rubberizeit than Pond Shield.
As for glass I'm going to do 1/2" thick 86" x 26". Is that good enough?

I wouldn't use subflooring plywood because it's not really stainable or paintable
 
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