Cleaning out the holding tank

[Glenn Walsh]

Can you use muriatic acid to clean out the holding tank and if so what is the procedure?

[gonesail]

i flush diluted acid thru my head to clean out the calcium deposits but not sure about the holding tank .. how will you get it out of there?

[stacy]

you might try bacterial culture that is found in hardware stores. It is used for septic tanks and leech lines. You can flush it into the holding tanks via your head or via an inspection port. We have used it very successfully in our holding tanks.

[Glenn Walsh]

I was thinking it could be pumped out at the pump out station

[dennisjay]

Don't use muriatic acid if your holding tank is made out of aluminum or other metals. It will eat through. Are you sure your holding tanks needs that kind of cleaning? Flushing with water usually does the trick. The acid is usually just used on lines going from your toilet to the tank (you first need to remove the line from the holding tank to do this) to remove scale buildup.

Be careful with muriatic acid. It's nasty stuff.

[Glenn Walsh]

The tank and the lines are plastic will the acid do any damage to the jabsco toilet

[sy_gilana]

You'd be better off with caustic soda...

[peghall]

You can...muriatic (hydrochloric) acid has been the accepted de-scaler for marine piping and sanitation systems for decades because it does the job without harm to anything in the system including toilets, and it's also safe to use in a metal tank. In fact, it's what Raritan recommended for cleaning out the Lectra/San till they decided to add a ready-to-use descaler to their sanitation and cleaning products line.

However, descaling is the ONLY thing that muriatic acid does...and in 25 years I've yet to see a holding tank that has enough mineral buildup in it to need it.

Dirty tank walls are coated with the animal fats in waste, not scale...a strong solution of liquid detergent (Wisk is good...a couple of gallons) in a tank full of water with a bag full of ice cubes is all you need to cure that problem...go sailing and tack a lot. Then flush VERY thoroughly with clean water.

Sludge, unless it's been allowed to dry and turn to "concrete" can be flushed out with just water (directions to follow)...but if it has turned to concrete, NOTHING will dissolve it that won't damage the system...you're stuck with it. But I've yet to see enough buildup in a tank to block the discharge or make a noticeable difference in the capacity.

The following should be done 2-3x/year, and especially in preparation for winter or other extended layup:
Pump out the tank, or dump it at sea. Then put enough water into the tank via the deck pumpout--'cuz that sends the water into the tank at the bottom to stir up the sludge and hold it in suspension so it can be pumped out--to cover the bottom to a depth of 4-6"...it can be fresh water at the dock or sea water using a washdown pump. Pump out or dump...repeat...repeat...repeat...till you're pumping or dumping clean water. Then one last time to rinse out any macerator and plumbing to it.

And while you have the hose in your hand, backflush the tank vent too.

If you're doing this in preparation for winter layup or extended storage, this should be done with clean FRESH water and also run through any macerator overboard discharge plumbing to rinse them out too.

And with that, my friends, I bid you a fond farewell. Email me if you need help.

[Glenn Walsh]

Thanks for your help