D. Miller. According to most algae can be treated when water temps approach the 60's. Algae is usually a battle throughout the year but the sooner you treat it the easier it'll be to contain the rest of the year. If you're going to apply early in the year you'll probably want to wait for a couple of consecutive good days with air temps in the mid 60's and sunny with not much wind. This way the chemical will stay in contact with the algae and will run it's course in the algae while it's growing at better rates. From what I understand at the recommended rates the chemicals shouldn't hurt the eggs or fry however it wouldn't hurt to avoid them. Around North Ohio I'd guess the bass would spawn around the middle of may and the bluegill will start their first bout of spawning somewhere around then also. I believe around water temps of 60-65 degrees is when you'll start noticing some spawning.