Muriatic acid to clean black water tank?

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Joined: 11/3/20
Posts: 1
Muriatic acid to clean black water tank?

I saw a youTube video extolling the benefits of using muriatic acid diluted with water to clean out the black water tank of hard deposits created by urine and salt water mixing. Has anyone done this and what mix ratio did you use. How long did you let it sit before pumping out the mix of acid and water. 

Ray Taylor's picture
Ray Taylor
Joined: 9/11/19
Posts: 81

Many people, myself included consider Peggy Hall to be a credible expert on marine sanitation systems.   I highly recommend her book “Get Rid of Boat Odors”.   I covers most aspects of marine heads and maintenance.    

I don’t want to quote her but I recall her saying that Muriatic acid works but it is damaging to other parts of the system.   She recommends other more gentle methods.  

A quick google search offers tons of information.    The point is she is a respected industry professional.

Ray & Janice Taylor
Hood River, Ore.
#2113 2002 TM

Catboat Willy's picture
Catboat Willy
Joined: 12/22/14
Posts: 385

In my opinion,Hydrochloric acid or muriatic acid at full strength is too strong for what you want to do and may damage other portions of the system. We've used this stuff called 'Septic Shock' with much success. Available at most hardware stores or Amazon.

Bill Dolan 1990 Catalina C-36 MKI - Hull #1041  'Williwaw'
Std. Rig, Walk Through, Wing Keel
M35, Oberdorfer Conversion,
Home Waters; Charlotte  Harbor & The Gulf Islands of Florida
'You are never out of work if you own a boat'


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