600 Gallon Plywood and glass


Feeder Fish
MFK Member
Aug 10, 2007
Why settle for the ordinary when you can build the extraordinary for less! We all dream of a monster tank but we all can’t afford to buy one. A tank of comparable size to the one I built made of all glass or acrylic will easily run you $3000+ USD and that’s not including shipping if you have to do so. It took me approximately 3 months of planning and designing and another 5 months to build, mostly due to not having the $1500 it took to buy all the materials at once. The first step for me was where to build. Obviously in a 77 year old house like mine or just about any other house, your limited to where you can build a tank that will hold 5000 lbs of water. For me there was only one place and that was the basement. Luckily I had a drain and water line close by in the location I planned the build. After I picked the location I had to see just how big I could go with the tank and still have room for filtration and tank access. The over all outside dimensions were 104.5”x 56.75”x67” with the inside dimensions of 96”x48”x30.5” for a total of 608.4 Gallons.


While I was waiting to start the build because the basement being waterproofed I found a cool free program from Google called Sketchup that I used to design the frame for the tank and to give me an idea of what the tank would look like once built and the wall put up. It took me a while to really get the hang of the program.


Once the waterproofing was done I got out the tape measure and chalk line to snap the lines where the tank base would be laid down so I could put the drywall up later and have nice square corners in the room.

Next I put down a layer of 2x6 that I would build the tank on making sure it was square then using Tapcons I secured the boards to the floor.

Next came the vertical risers using 2x6’s 12” on center then 2 layers of 2x6 overlaped in the corners for added stability.

I should also mention I used 3” deck screws for the base framing. In normal home construction floor joists and wall framing is placed 16” on center.

Over top of those I used 2x8 as horizontal joists 12” on center and placed directly over top of the 2x6 risers. Since I couldn’t place every joist or riser 12” OC all the way across I started on the ends and worked my way in the center staying 12” OC then when I got to the center I just split the distance and placed a riser and joist in the dead center.

After the base of the tank was done it was time to start framing the walls of the tank itself but now using 2x4’s and 2.5” drywall screws. I started off the same way as the base but I used 2 layers and overlapped the ends for extra stability. The once again keeping everything 12” OC I finished framing in the tank and ended with another double layer on top with overlapped ends.

Now that the Framing was done I used 5/8” plywood only because I got it for free where my original plan was to use ¾”. I used 2” drywall screws about every 6”-8” to secure the plywood to the 2x4’s

When the plywood was in I measured out where the bulkheads would go which was 2/3 the way up the side of the tank so all I would have to do is open a valve and 30% of the water would be drained then close the valve and refill. I drilled the holes out now so that when I sealed the tank I could also seal the cutouts in the plywood as an extra precaution. Before the sealant could go on I needed to cover the screw heads and fill in the seams with something that would bond to wood and the screws and have the ability to let the 2 part epoxy bond to it and for this I used plain old automotive Bondo which I learned from some door installers at work holds very well to wood.

Now that the framing and plywood was in place I used Sweetwater Epoxy from Aquatic Ecosystems Inc. for the sealant. I had read of others using drylock and other marine grade sealants but the Sweetwater brand was specifically made to be fish safe. And it was only $57 per gallon with a $20 hazmat shipping fee.

Before I used the epoxy I had to get painters plastic to seal the area I was working in from the rest of the house so I wouldn’t chase the family out of the house from the fumes.

I also went with two colors of Sweetwater thanks to a tip from someone else that had used the product who informed me it was much easier to tell if you missed any spots when applying additional coats or if I was applying to thinly.

I also sealed the back of the plywood where the bulkheads were in case of any leaks.

To apply the epoxy I used normal solvent resistant ¼ nap rollers and mixed the 2 epoxy parts in graduated plastic paint containers from Sherwin Williams. The other nice benefit of the Sweetwater Epoxy is that it has a good working time especially for first time users such as myself and there is no sanding required between coats.

After the Epoxy was applied and set for a week I cleaned the surface in preparation for the glass with a non-sudsing ammonia as the directions suggested by AES and started dry fitting the plumbing. For the plumbing I used 4x 2” bulkheads and 2” PVC to the sump and on the return from the pump I used 2” pipe I had left over then built under gravel jets using 1” PVC so there wouldn’t be any dead spots in the tank and to keep the waste suspended in the water until it can get sucked out to the filter. To make the jets I used 2” cut pieces of 1” PVC heated up and pinched with pliers.

For the glass I used GE Silicone I Window and Door. Be careful not to use Kitchen and bath silicone or any other silicone that has mold and mildew inhibitors like the kitchen and bath or the new GE Silicone II with the bio-seal. The glass dimensions are 84”x29”x.5” Tempered. Getting the glass in was a little tricky we used towels so we wouldn’t gouge the epoxy coating then laid the glass flat in the tank the applied a thick bead of silicone around the edge being very careful not to misalign the glass with the opening when putting it in place. Then when the glass was in place I used clamps and 2x4’s with towels around the ends to protect from gouging the epoxy.

Once the glass was In I used pieces of EMT with the ends flattened and holes drilled in them for the 2” bolts that would hold them in place to keep the tank from bowing once filled.

I also filled the predrilled holes in the top of the tank where the bolts went with silicone before putting them in. Now that the glass was in I waited 7 days for the silicone to fully cure but in the meantime I finished the plumbing by gluing the pipes together. The reason for the way the pipes are run is to make it just like an over flow. the water lvl in the tank depends on where the pipe starts to go down.

The reason the pipe is open on the top is to stop any siphon effect. Its also a great place to dose any meds.

The pipe running to the ground is the drain pipe and the one you se at the top of the pic is the ball valve used to adjust the flow from the pump back to the tank.

The only place I didn’t glue the pipes was where they went into the bulkheads to hold them in place I wrapped the PVC pipe in a few layers of Teflon tape then pushed them into the bulkheads. Almost a year up and still no leaks using the Teflon tape. For the sump I used 2 cleaned out Brine tanks from whole house water softening units. Ones a 40G and the other a 30G. I had to connect the two with a siphon tube because there was too much draw from the pump to only use the 40G. Combining the two gave me more water reserve to work with.

For mech filtration in the sump I use egg crate covered by foam filter pad and filter floss underneath that.

Bio Media for the sump

The pump was originally a Beckett 3500 GPH pond pump but even with a ball valve in there I couldn’t get the flow reduced enough to keep it from blowing the fish all over in the tank. So I ended going with a Gen-X submersible 8500/lph pump (about 2300gph) which I still needed to tone down with the ball valve. For secondary and mainly Mech filtration I used an FX5 which works great.

For lighting I used 2 basic 4’ double T12 shop lights but I have plans to soon upgrade them to T8’s so I can plant the tank.

The substrate in the tank is 400 lbs of well rinsed leveling sand from Home Depot and the driftwood is from Lake Erie. When I originally set out to build this tank Ihad the intentions of stocking it with Malawi cichlids then before I was done building the tank I changed my mind and went with SA cichlids and an arowana only to find out in the winter time it cost me about $40-$50 just to heat the tank So I made the decision to go with North American Native fish. Which I can honestly say I’m extremely happy with.

All thats left now it to finish the drywall, paint the room add the trim to the viewing area of the tank to "picture frame" it in then some updated lighting and new carpet and I can sit back watch the fish swim and catch the game in the Man Cave! :headbang2 which is right next to the Laundry room...:banher:


Feeder Fish
MFK Member
Aug 16, 2007
very nice work. love it. how long it took you from start to finish?

Eleven Bravo

Feeder Fish
MFK Member
Aug 12, 2008
:headbang2 amazing. Awesome job!! cant wait to see it stocked!


Blue Tier VIP
MFK Member
Aug 27, 2008
Very cooL, nice Work!


Feeder Fish
MFK Member
Sep 29, 2008
NW Indiana
Great work Bob the Builder...lol...the tank it awsome...wish a had any sort of creaftmanship...thanks


Jack Dempsey
MFK Member
Sep 3, 2008
Brisbane, Australia
great job