Don, I had this problem before. (Sounds like you have a good DI system) We had to make a portable vacuum/scrub/filtration system that we would weekly sweep/mop/scrub the rinse tanks to remove this beast. I couldn't find a way chemically to do this (but I also didn't have Technet's exposure either). The good thing was that the portable vacuum could also be used to capture any fiberglass and metal particulate that accumulated at the bottom of the tank. Groovy ______________________________ Reply Separator _________________________________ Subject: Fungal contamination Author: [log in to unmask] at SMTPLINK-HADCO Date: 2/13/96 8:34 PM Has anyone had any exposure to fungal growths in thier plating line rinse tanks (especially after the acid cleaner). This hyphae is quite hearty and nothing seems to kill it. It is not an algae. I've even tried glutaraldehyde, a common antifoulant used in the metal finishing industry, to no avail. What does anybody say? Don Hoppe Jr. ZYCON [log in to unmask]