Snub provides very good advice. Treat the FA early as soon as you can see it greening up on the bottom spread some Cutrine granules. FA always starts growing on the bottom than later it breaks loose and floats, but by then it is quite difficult to control.
Headed to town today to try to find some treatment. I think I remember seeing it before, hope they still have it. It's gotten cold again and the FA bloom we had a few weeks ago has dissappeared, I think this might be a good time to start looking for it on the bottom and treating it.