The products used to clean raw water passages may also dissolve zincs. If so, remove before using, or replace when finished. *Rudy & Jill Sechez * *BRINEY BUG-a 34' Sail-Assisted Trawler * *Anchoring Consultants-trawlertrainingabc.com* *850-832-7748 * *New Bern NC Northbound-Chesapeake*