Barnacle Blaster Concentrate - 32oz. Features:. Removes deposits on boat bottoms, scum line and rust stains quickly and easily. Special ingredients to quickly remove barnacles and clean rust, oil stains and algae. You've never seen anything like this! Barnacles literally begin to fall off the hull of the boat!. Requires very little scrubbing. Will not harm fiberglass or gel coat. Can safely be recirculated through sea water cooling systems, dissolving barnacles, zebra mussels, calcium, rust, lime and all other mineral deposits. Water based, environmentally friendly formula. Special buffering process makes this product safer than other acid-based bottom cleaners