Acrylic Tank with a Plywood Bottom

Okay so I got a 4 x 8 sheet of 1" acrylic and cut it to 2 x 72 x 24 and 2 x 24 x 24 so the tank is 6 feet long 24 in tall and 24 deep. Right around 180 Gallons. I got the sheet for free and instead of buying an acrylic piece for the bottom i decided it would be more cost effective to build a plywood base. My Local acrylic store wants $150 for scratched up piece of 1/2. When Plywood is $20 at Home Depot and Thicker. So far I have fiber glassed the inside 2 times with cloth going one direction the first time and opposite the second. I did a total of the three layers around all seams on the in side where the plywood meets the acrylic. and also did the outside and it was leaking . So i had a elastoméric silicone paint and did about 4 coats outside and 2 inside and it is still leaking... i am about $75 into this, I am probably going to peel all the silicone off or leave it and do something on top ... Just very weird that its not holding water ... ANY IDEAS ? also i used 3m 5200 on the bottom of the acrylic to the plywood and used weld on 4 for the acrylic panels and weld on 16 for the gaps as Joey shows....