I know this is an ancient thread... But I am gonna bring it back to life...
I have been doing a ton of research and I am gonna attempt a plywood tank myself... 300+ gallons..
I am gonna use "pond sheild" epoxy I think... Instead of liquid rubber... It's a bit more expensive.. But comes in any color and when it dries.. It's very smooth and suction cups stick to it perfectly...
But.. I am wondering how the OPs tanks with the liquid rubber and paint held up... If it is still good.. I may go that route... But at the same time.. The pond shield is only about 100 bucks more and silicone sticks to it with no problem at all..
Anyways I hope the OP sees this and will respond with an update for all of us
BTW everyone... Including the OP built some beautiful tanks... Good job!!
I am going to star buying material next week..
I want to go 8 foot wide... And probably 30 x 30 deep and tall.. I still have not totally decided on that yet