Welcome to the forum Mark!

First, pH can swing wildly throughout an average day. At night. plants respire carbon dioxide, which becomes an acid, and lowers the pH throughout the night and early mornings.....the calcium in the water will then neutralize/buffer the acids and pH will rise all day and into the evening.

A pH of 9 seems kind of high...I'd test for alkalinity and hardness with calcium and other mineral salts to try finding why pH is so high.

I'd hold off on fertilizing...what is clarity (depth you see into the water) and the color.....is it a deep green? Fertilizing could cause a massive algae bloom that gets too dense, dies in a couple cloudy days, and consumes all dissolved oxygen in the water that ends up suffocating all the fish....

With fish 5 years old or more, there should be many lunker bass, large crappie, and 10"+ gills lurking in the water...

With that many acres, I'd bring in a pro to evaluate the lake....

Last edited by Rainman; 04/21/18 11:09 AM.