The guy from the extension office came out today and he believes that a huge algae bloom caused the DO levels to drop significantly causing the small fish kill. He didn't seem to concerned about the ph although it is still at 9.3-9.4. He told me to just keep running the aerator and not to fertilize for a while since my visibility is around 10-15 inch. I'll be keeping a close eye out for some more dying fish over the next few days. Thanks for everyone's help