I use the Total Boat ablative bottom paint in Lake Superior, mostly bays, etc. Not a lot of big water unless it's nice and calm. I moor in a small and fairly stagnant bay. There's not a lot of water movement so the water is pretty green all season. It's worked fine for me for ~ 6 years. I do get some slime, but nothing that a scrubby pad wouldn't easily remove. Usually we don't bother during the season.
I pressure wash when we haul out in the fall -- just a light cleaning to get the majority of the slime, etc. off. Then in the spring I do a much better pressure washing job when I do the deck, etc. Basically blasting off anything that wants to come off. Then roll on another coat.
My boat is small enough that a gallon lasts me 2 seasons. I keep the can in the basement where the temperature is fairly constant (no idea if it helps) and usually add a little of their brushing thinner (not much) if feels too thick. About the only thing "special" that I do is use a cheap drill-powered paint mixer to make sure that all of the solids are back in suspension before I start.