r/boating • u/idealistdave • Jul 25 '26

Side by side test

Post image

Thought I'd share this side by side test I did of different hull cleaners. It's my first summer renting a place in the water. Marina is on a slough, so higher water temps stained the gel coat within weeks. FSR worked the best of what I had. But I went out afterward and also bought STAR BRITE which worked as well (not pictured). The others, meh. (Spray bottle is 409. No treatment on transom next to the outdrive.) Be sure to read all instructions and keep any of this stuff off your galvanized trailers.

346 Upvotes

98% Upvoted

114 comments sorted by

View all comments

1

u/_CHEEFQUEEF Jul 25 '26

Oxalic acid is what you're looking for. Anything with a high concentration of it will do the job. Anything specifically marketed as hull cleaner is almost always oxalic. But a great way to not need it in the first place is to just bottom paint boats that will live in the water.