Congrats on the new pond!

I am not an expert on the lime requirements for ponds. However, the purposes of adding lime to agricultural ground versus adding it to ponds are different.

We have several experts on the forum for your topic. Hopefully they will comment on your thread.

P.S. Have you read any of the good threads about adding structure to your pond? It is much easier to emplace BEFORE your pond fills.

Good luck on your pond project. 3.5 acres and 15' deep sounds like a beaut!