I sprayed a diluted solution of Cutrine Plus on floating mats of algae a couple of weeks ago, but nothing happened.

I then sprayed undiluted CP on the same mats last week. The algae is still showing no signs of dying.

Why isn't the FA dying back?

Earlier this summer, I used a different brand of algaecide that killed the FA in a matter of a couple of days, but I can't recall the brand or the active ingredient and the place I bought it does not have any more. I think it had orange lettering on the jug.

Any input is appreciated.