Re: Lake scum
Are the pontoons aluminum?
If so, my neighbor uses a mixture of 1 part Muriatic acid to 10 parts water in his pressure washer, and follows up with a good all water cleaning. Don't leave the mixture on as it will discolor the metal if left for too long.
It might be wise to use a respirator or a dust mask at the least since a pressure washer throws off a lot of mist. Eye protection is a must.
I have used Purple Power in my pressure washer on fiberglass hulls and a fiberglass canoe that I have, and it works well too. I dilute it to 1 cup Purple Power to 1 gallon of water. It's actually ok to leave this stuff on full strength for a few minutes before you wash it off. You can get it in the auto section at Wal-Mart for around $4 a gallon last I checked. If you are sensitive to chemicals where gloves with this as it is a mild alkaline cleaner.
