Purging Fresh Water Holding Tank

[MCADRG]

I have a 1991 Carver 3698 aft cabin. I need some help to understand the best way to clean/purge and discharge my freshwater holding tank. Thanks.

[Viper]

In the Spring, after you commission the fresh water system, pour some Camco TastePure Spring Fresh water system cleaner and deodorizer into your fresh water tank. I like starting this off with an empty tank. After you add the fluid, add enough water to the tank to allow you to run the mix throughout your entire water system. You can do it with your hot water tank hooked up or by-passed. Run one faucet at a time until you see some of the mix come out of the spout. You'll know when that happens by the fiz/bubbles and fresh scent. Don't forget the ice maker if applicable. Leave the system full of the solution for a while, it tells you on the container how long but I leave it overnight. Then run the faucets until the solution is all gone, fill the tank with fresh water and rinse the system by running all the faucets again. This usually does a good job of cleaning the tank and the lines but it won't do anything about sediment sitting on the bottom of the tank. I do this every Spring.

Fresh water pumps have a limited duty cycle so don't run it continuously long enough to empty your tank. Run it for about 10 minutes then let it rest for a while. This will prolong your pump's life. Once you empty the tank of the fresh water to rinse the tank and system, you could switch over to dockside water and continue rinsing the hot water side as it will take longer to rinse the hot water tank if it wasn't by-passed for this process.

[MCADRG]

Thanks Viper, much appreciated.

[MCADRG]

Viper, I have another question for you. What if I wanted to purge my freshwater holding tank with the Camco Taste Pure but discharge it overboard without running it thru all the on board plumbing? Is there a way to do that? Thanks.

[Viper]

I'm sure one can come up with several ways to do that but the easiest is just running it through one faucet. Depending on your setup, you can disconnect the outlet hose on the tank and just let it drain into the bilge. Just make sure your bilge pumps are working. You don't want to do this if your tank is in a position that will cause water to end up on your floor or inside a cabinet and damage woodwork. You can also disconnect the outlet line from your fresh water pump, hook up a hose long enough to go out a window or hatch, then turn your pump on. You can also lay the hose in your shower and it'll just drain into the sump which will pump it overboard. Lots of way to do it.

Why don't you want to run the solution throughout the entire system?

[Cooler]

Not sure if this is a "best practice", but you can connect a pump out fitting on your water tank fill connection. Just takes the correct size connector to the water tank fill flange, which most marinas have. The only reason I know this is I once instructed a dock hand to pump out the head, and he erroneously pumped out the water tank. Figured out when I could not get head to flush, as it uses water from holding tank as source. Yes, I was a little worried about backflow from sanitation hose. There was no issue with that. Good luck. er

[MCADRG]

Viper, to answer your question; we bought the boat in 2019 and have never used the fresh water tank. The previous owner did use the tank. My concern is flushing whatever may remain in the tank as far as degraded marine plumbing antifreeze ect. thru my boats potable water systems. Plus, I don't really want anything discharged over the side which could stain or discolor my hull. I would like to do a first flush with the Camco Taste Pure overboard and then flush again thru the freshwater system onboard.