This is got to be the worst part of s plywood build.
How many layers of fiberglass do us use?
I did 3 layers on the walls and 6 on the corners. 6 layers of Epoxy and then 3 layers of pond armor. In my opinion none of that was structural, just to keep the water out and the seams from busting. The wall I built around the tank is what keeps it from Bowing.
Keep up the good work!