Solvent to remove buildup on hull?

I have an 05' 350mag mpi with an Alpha one drive. The previous owner had the boat slipped for 4 years and used it rarely. there are only 80 hours on the boat. There is significant buildup on the bottom of the hull and I believe the plant matter may be hindering my WOT RPM as it currently maxes out at 4350.
Anyone had a good experience with a particular product?

Re: Solvent to remove buildup on hull?

YES the growth is slowing you down. Get it off before you run the boat anymore, or you are risking engine damage. (Lugging causes high combustion chamber temps, which deforms the valves).
Any oxylaic (spelled wrong, I know) acid based product will work. Including, but not limited to toilet bowl cleaner, Mary Kate On/Off, Starbrite Hull cleaner. I had just as much sucess with The Works toilet bowl cleaner as I did with Mary kate, for about 1/10 of the price. Others have mentioned muriatic acid (pool cleaner) diluted a little.
All the cleaners are caustic, so eye, mouth, and hand protection is recommended. Don't spill it on your trailer (especially if it's galvanized) and rinse it right away if you do.

Good luck.