I am in New Jersey , zone 6b -7 . My pond project is circular at 6ft across 3 ft deep. close to 700 gallons. I plan on doing several goldfish and pond plants . I will put a fountian in the middle and an aireator .I'm thinking now after reading alot of posts that I should dig deeper to .3 1/2 ft . because it's a full sun location and I'm worried the fish will overheat in the summer and stress in the winter. The pond does get afternoon shade . Can anyone share your expiriences with depth ? and thaks !