265 Gallon Leaked...Considering a plywood build to replace it....

[spas]

Hello,

I have been reading all the plywood tank builds over the years and when my 3 year old 265 gallon Marineland sprung a leak 2 weeks ago I have lost all faith in all glass large tanks and now considering building a plywood tank as a replacement.

Since I have this opportunity I thought why not go big. I am planning a 96" x 48" x 30" or 32" (not sure yet). I was a planning on using the front pane of glass from my 265 (84"x30" x 1/2" or 12mm).

First question - would this piece of glass by thick enough for a tank this size? If not, if I reduce the depth to 36" would that work? What about the height - if I go 30" tall I would make the front opening 80"x26" or 81" x 27" to leave 2" or 1.5" silicon sealing surface. Which would be the recommended amount of space to secure the glass 2" or 1.5"? If this glass is too thin, could I double it using my existing front and back pieces (this would be very heavy on the from side of the tank).

Second - I watched the DIY King Joey's build where he essentially laminated 3/4" plywood together without any additional 2"x4" for the sides and back, is that method strong enough for a tank this size? I notice some plywood builds on here where people frame the back and sides with 2"x4" every 12". Is that overkill or a safer method?

Finally, I noticed Joey just used Pond Armour to seal the inside of the tank - he didn't fiberglass the panels first. Again is it necessary to fiberglass the entire interior or just fiberglass the joints and seal with several layers of Pond Armour?

Thanks again for your guidance!!!

 

[M1A1]

Hello,

I have been reading all the plywood tank builds over the years and when my 3 year old 265 gallon Marineland sprung a leak 2 weeks ago I have lost all faith in all glass large tanks and now considering building a plywood tank as a replacement.

Since I have this opportunity I thought why not go big. I am planning a 96" x 48" x 30" or 32" (not sure yet). I was a planning on using the front pane of glass from my 265 (84"x30" x 1/2" or 12mm).

First question - would this piece of glass by thick enough for a tank this size? If not, if I reduce the depth to 36" would that work? What about the height - if I go 30" tall I would make the front opening 80"x26" or 81" x 27" to leave 2" or 1.5" silicon sealing surface. Which would be the recommended amount of space to secure the glass 2" or 1.5"? If this glass is too thin, could I double it using my existing front and back pieces (this would be very heavy on the from side of the tank).

Second - I watched the DIY King Joey's build where he essentially laminated 3/4" plywood together without any additional 2"x4" for the sides and back, is that method strong enough for a tank this size? I notice some plywood builds on here where people frame the back and sides with 2"x4" every 12". Is that overkill or a safer method?

Finally, I noticed Joey just used Pond Armour to seal the inside of the tank - he didn't fiberglass the panels first. Again is it necessary to fiberglass the entire interior or just fiberglass the joints and seal with several layers of Pond Armour?

Thanks again for your guidance!!!

Depth of the tank is the most important factor for glass thickness since water pressure increases only with depth of water. Length of the piece of glass is a small factor but only really comes into play when we're talking rimless tanks, not eurobraced or plywood-cutout type. So, in my opinion, 1/2" is fine for a 30" water level assuming a 1.5" sealing surface. I see no reason at all to double it with the existing back & front pieces; save the extra piece for another tank.

I believe the 2x4 studs are more common on larger builds where a single piece of plywood won't cover a whole face (>8' or 10'), or where the height is more than 4' or so. Quality plywood and construction methods will be sufficient in my opinion.

I have no comments on Pond Armour or Joey's builds. How much you fiberglass is up to you - corners only, edges only, whole interior, interior and exterior... Fiberglass has its benefits but it is an additional cost and is fairly labor intense.

 

[Homer Siped]

I WAAAYYY overbuilt mine, but I'm not worried about it blowing apart lol. I knew very little about big tanks when I started mine, soon got a crash course in it all. I fiberglassed all inside of mine, it's not as bad as you may think. I framed mine with 2x4s and used 3/4 ply on inside. From my understanding half inch is good for about 30" deep. Can go taller as long as your glass is in top 30" I think?