Large tank stand top - Coosa Board?

chome360 · Feb 27, 2026

I'm trying to pin down the ideal top to my new stand. Tank is 440 gallons, 86 in long and 42 in wide. Stand is alufab, mostly of 3x3s. 12-In gaps in between the support beams on top.

I was originally planning on going with starboard, either 3/4 inch or 1 in thick. The more I look into it the more it sounds like starboard can "creep" over the years. Seems that Marine plywood is the safer bet, a beast as far as avoiding creep over time. I'd really like to stay away from wood in this project, brought me to coosa board.

I don't want to reinvent the wheel here, and I can't find anything from anybody else about using coosa board, which seems like a red flag. But everything about it seems perfect for the job.

Anyone use this before?

mpatterson42 · Feb 27, 2026

Did you talk with Alufab about their PVC top? The guy in this video got something directly from them for his top and sump area.

Go to the 1:25 mark.

chome360 · Feb 27, 2026

mpatterson42 said:
Did you talk with Alufab about their PVC top? The guy in this video got something directly from them for his top and sump area.

Go to the 1:25 mark.

I did, but shipping costs didn't make it make sense for me when I can just buy the same thing locally and pick it up myself. I think that's just due to the size of the sheet I would need. But in searching for to get this, started looking at regular HDPE vs starboard vs other options.

That was a great video though, ended up helping me on some assembly steps that I was stumped on!

mpatterson42 · Feb 27, 2026

Makes sense. I don't know anything about coosa boards but a quick search and I think you'd be OK. Maybe put a thin foam mat between the board and the tank though.

chome360 · Feb 27, 2026

mpatterson42 said:
Makes sense. I don't know anything about coosa boards but a quick search and I think you'd be OK. Maybe put a thin foam mat between the board and the tank though.

Agreed, yeah my tank has the foam mat already glued to the bottom of the tank. Not sure yet on the thickness though.

Just seems strange to me that I can't find anybody else who's used coosa board. I don't want to be the first one to do it! Haha

salty joe · Mar 1, 2026

Never heard of Coosa but it looks perfectly fine as long as it doesn't compress.

By 'creep' do you mean sliding off the stand?

Why not 3/4" pvc sheet from lowes? Wht not plywood? I used plywood on my big tank with no issues.

chome360 · Mar 1, 2026

salty joe said:
Never heard of Coosa but it looks perfectly fine as long as it doesn't compress.

By 'creep' do you mean sliding off the stand?

Why not 3/4" pvc sheet from lowes? Wht not plywood? I used plywood on my big tank with no issues.

Creep meaning a very small amount of sagging between my supports (12 inch gaps) over a very long period of time. Tank us 440 gallons. Supposedly marine plywood performs the best, coosa board second (1st if you stick with none wood) and starboard 3rd with standard HDPE after that.