How to remove sludge from Fresh Water Holding Tank?

Skipper July 10, 2012 Ask The Skipper

Charles Doucot asked:

Can you help me?

I have used several of your products and they work great!

I have a problem with sludge in my fresh water holding tank and the tank is inaccessible. Is it possible to use Bilge Bath in the tank to break up the sludge so I can pump it out? The tank is plastic and we use the fresh water for bathing and washing dishes.

Answer:

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The sludge in your fresh water holding tank is probably fungus, mold, or algae. This condition often occurs during winter lay-up. that’s why it important to satirize your tank each spring or twice a year if your boat is in constant use for the entire year.

To rid your tank of this sludge, you can use Green Genie. Green Genie is corrosive to metal, so I assume that since you water tank is plastic, that all the hoses and fittings will be either plastic or rubber, which will not be harmed by Green Genie. Drain the tank and then pour in a full bottle through the water fill fitting. if the fitting is metal, you can rinse the fitting with water where Green Genie has come into contact with it, or if you can, use a funnel to prevent it from contacting the metal fitting.

Take the boat out for a cruise or sail, being sure to turn from side to side and accelerate and slow down so that the Green Genie sloshes throughout the tank. about 20 minute will be enough. Next fill the tank with water and drain it completely. Fill the tank again and drain it. This should get rid of the sludge. Next it’s important to sanitize the tank using the following procedure. You should also sanitize your tank each spring with the same procedure.

Fresh Water Holding Tank Sanitization Procedure:

1. While filling your tank to maximum capacity with potable water, add 1 cup of chlorine bleach for each 40 gallons of tank capacity. Open all of the water taps to insure that the mixture runs through the hoses and fittings. Top up the tank with potable water.

2. Wait for 24 hours and then drain the tank, running the water through all of the taps.

3. Fill the tank with potable water and drain through all of the taps.

4. While filling the tank with potable water, add 1, cup of vinegar for each 40 gallons of tank capacity. Open all of the water taps to insure that the mixture runs through the hoses and fittings. Top up the tank with potable water.

5. Wait for 24 hours and then drain the tank, running the water through all of the taps.

6. Fill the tank with potable water and drain through all of the taps.

7. Fill the tank with potable water and enjoy

NOTE: Be sure that the water you are using is safe for drinking. Normally potable water supplied by a municipality is safe bet check to be sure. This is especially important when you are cruising and not at your home port. Using an activated charcoal / ceramic water filter in line with your dedicated drinking water tank is also advisable.

Thanks for your question,

Captain Aurora
Richard Kittar