DIY - Projects & Ideas • 300 gallon plywood tank build

[rotccapt]

hi all i am just getting started on my 300 ish gallon tank. the tank will be built with a 2x4 frame but instead of the 2x4's being oriented like a wall they will be turned 90 degrees so the long side of the board will be parallel to the tank sides. the bottom of the tank will be a solid piece of 3/4 inch ply and the back and one side will be 1/2 inch plywood. the front and the other side will be 3/8 inch glass. the external dimensions of the tank will be 76 inches long 36 inches wide and 29 inches tall. there will also be a 12 inch tall hood/above tank basking area for my western painted turtle. the inside dimensions will be 72 inches long 32 inchs wide and the water level will be 26 inchs high. the stand is also 29 inches tall and will be doubling as a dresser since this tank will be in my bedroom. i will be using "MAX ACR epoxy and fiberglass cloth to water proof the tank.

for decor i will have a large drift wood stump that i found in a local river it has been drying out for about a month now and i will be dumping boiling water over it and it will soak in the tank for the entire fishless cycle. i will also have another smaller driftwood stump that i had in my last tank along with some rock piles. i will also be using tan pool filter sand for substrate. the background will be a custom foam and drylock rock wall that will consist of lots of overhangs and caves.

stock list will be:
1x tiger oscar
1x salvini
1x green terror
2x nic
2-4x fire mouth
5x bala shark

so far the i have the stand framed out and im about to start on the drawers.

so on with the pics.

drift wood

background i am going to try and recreate

tank

stand

[quentin8]

NICE Keeps us updated..

[13razorbackfan]

[rotccapt]

well been busy at work so not much progress but the stand is almost complete. i still have to build the drawers and attach the plywood top i hop to get it done this weekend. then i will start the tank frame

[cantrell00]

What are you using to make the interior water tight?

[rotccapt]

i will be using MAX ACR epoxy and fiberglass cloth to seal the tank and will be using GE silicone I for the glass

[rotccapt]

well got some more work done on the stand today. i have all the rails installed for the drawers and have all the material except the bottoms cut and routered so i am ready for more pocket holes and assembly. in the pics you will notice there is a large space behind the drawers this is for the sump which will run the whole length of the stand

[13razorbackfan]

Looks sweet so far...great craftsmanship.

[mel_cp6]

Looking good so far. I'll be following this thread till its done as i am looking into building ply tank myself.

[rotccapt]

well guys sorry for the slow progress. but here is a few more pics of the progress. i have three of the drawer frames assemboled and installed i still need to cut out the bottoms for the drawers and drill a ton more pocket holes

[Mr.Dempsey]

Looking good man! Keep up the good work!

[bernie comeau]

the back and one side will be 1/2 inch plywood. 3/8 inch glass.29 inches tall.

I supose with the 2 x 4's, even turned sideways, the tank will be very strong.....but 1/2" plywood really is very feeble stuff compared to 3/4". Though fiberglss adds a lot of strength

I doubt 3/8" glass is advisable to be used on a 29" deep tank. Unless it's tempered. Tempered does have one potential disadvantage.....might be dangerous if anything very hard hits it with some force as it will blow, unlike plate glass which is inclined to crack. Don't beleive I have ever seen a tank 6 ft. long, 24" deep or more, that is not 1/2" glass. A standard 90 gal. is the deepest tank I know of that uses 3/8" glass.....24" deep but it's only 4 ft. long. And of course, there is a lot more pressure, with every little bit of depth. IMO, if it's plate glass, definately should be going with 1/2".

[rotccapt]

well i was discussing it with my wife and we have decided 1/2 inch would give us better piece of mind

for the 1/2 inch ply i was basing my design off another build i saw that was bigger than mine and the person used 1/2 inch OSB but the sides of the tank were built like walls and the tank was taller than mine too.

[bernie comeau]

well i was discussing it with my wife and we have decided 1/2 inch would give us better piece of mind

That would be wise!
Other thing i just noticed is your tank is not braced in the middle. Wood is pretty strong but it definately will bend under pressure, over time. My 100 gal (48" X 24" x 21") was not braced across the top. It was very well fiberglassed, with 2 layers of fiberglass on 3/4" plywood....sturdy, yet over the course of 25 + years has become quite rounded across the back! My 180 gal. (6' X 2' x 2') has angle iron frame. The two iron strip braces in the middle across the top, rusted away over the years. The front is very heavy 2" angle iron, the back much lighter 1" angle iron. During the many years, with out middle brace, the back is some what rounded across the top, despite the 1" angle iron. I have since re-fiberglassed (2009) the tank, inside and out including fiberglassing the iron frame and added a glass brace across the middle of the top (2 peices of 1/4" glass stacked on top of each other siliconed to the iron frame).

[rotccapt]

i have not decided yet how i want to brace it. for now the top of the tank is a 2x4 with a 2x3 screwed to it to create a 90* angle glued and screwed every 6 inches. my plan was to fill the tank and have a gauge on the front and back of the tank and see how much it deflects with water in it. my thinking was no more than 1/8 inch total deflection would be acceptable any more and i will put a center brace in. my plan for the brace is either a 3 inch wide piece of 1/2 inch acrylic or a 3/8 diameter aluminum rod leaning towards the rod