Glass vs acrylic for a 10,000 gallon pond.

[BOBKAH]

I used 3/4 inch tempered glass for a window in my 5000 gallon pond. I plan on building a 10,000 gallon pond/tank. The tank will be concrete with 4 windows 40" x 52" . I am thinking I should switch to cast acrylic. Any thoughts or suggestions??? How thick would I need to go??? I found the formula online for a whole tank..... I assume it would be different for windows. Any help would be appreciated.