Enzyme cleaners for tanks and blackwater pipes

Oct 26, 2026
1
Hallberg Rassy 55 Cowes
I've read a number of threads on this forum regarding using enzyme cleaners for holding tanks and pipes, but I'm cruising outside the US and haven't found any of the enzyme cleaning products referenced. I have a stainless steel holding tank, fresh water flush and no toilet paper gets flushed. In order to clean the accumulated waste in the tank and pipes that I assume must be there after 14 years of use, I'm looking at using enzyme tablets available from a janitorial supplies company in the UK (BioHygiene - Urinal & Toilet Cleaner) i.e not made specifically for boats. Is this a bad idea? Thanks for your advice!
 
Jan 11, 2014
14,226
Sabre 362 113 Fair Haven, NY
The issues with household and commercial toilet cleaners is their negative affect on the rubber and plastic parts in most sanitation systems.

I've not tried it yet, however, dishwasher detergent may be an option since is its designed to loosen dried grease and food debris from dishes. Throw some in the tank and go sailing letting the boats motion agitate the cleaning solution.
 
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Likes: rgranger
Jan 19, 2010
13,061
Hobie 16 & Rhodes 22 Skeeter Charleston
I like @dlochner 's idea about a strong detergent. I have also wondered about using products designed for septic systems. I'm thinking about something like RidX liquid
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I don't have ANY experience using this on a boat but I have used it a lot. I raised a family of 4 kids (6 of us in total) in a house on a septic system. I was very diligent about using this once a month. After 15 years we had the septic guy come out to pump the tank and he said it didn't really need it. Everything was still open and flowing. This is enzymes plus "good" bacteria. I can't imagine how it could hurt to try it.