I have already pressure washed and then scrubbed the sides but there is still a light green water line visible. Would an acid cleaner be too much?

I used Starbrites Green Hull Cleaner and it came off with some scrubbing. If all else fails there is that rubbing compound by 3M.

starbright "hull cleaner" is awesome. from greenish brown to bright white. spray it on hose it off. <BR>

Sno-Bol toilet bowl cleaner. Cheap, and easy. Don't forget to put a nice coat of wax on afterwards. <BR> <BR>Eric

i second the star bright cleaner. it works great just don't get any in your eyes

Castrol Super Clean &amp; a good boat brush will get just about anything off! <BR> <BR> <BR>

muratic acid - rinse off well. Wear protection. Be sure to rinse off the trailer. It will corrode any unprotected metal if allowed to sit on it.

Davis FSR (Fibreglass Stain Remover). Removes algae lines every time!

Aaron, <BR> Karl is right. Wear glasses and gloves. All of the products mentioned above will burn you skin and eyes. I use Star Bright and it works wonders.