Drinking water additive

[Bob Ohler]

I had been adding Aquabon from West Marine to our water tanks. That product has been replaced by a private label product. Both products work well for keeping the water in the tanks fresh smelling.
My question is, what is everyone using as a water additive in their on-board water tanks?

Thanks.

Bob Ohler
CD30 #335
Past CDSOA Commodore

[wikakaru]

Chlorine bleach, around 1-2 parts per million. I use it to treat the 6,500 gallon cistern that is the only drinking water supply for my house as well as the water tank on my boat.

FYI, you can't smell chlorine at about 1 ppm, and the smell is faint at around 2 ppm. So if you have a very faint smell of chlorine from your faucet, you are in the right ballpark. If the smell has gone away, re-treat. In my house I do a daily check of the water with a Hanna HI701 Free Chlorine Colorimeter (https://www.hannainst.com/hi701-free-chlorine.html) and I vary the amount of chlorine added as conditions in the tank warrant. (It changes based on usage rate, temperature, and inflow rate to the cistern, which is itself dependent upon rainfall.) On the boat a simple nose test is fine.

It is getting harder to find plain chlorine bleach these days--much of it is scented or "splashless", which both have additives. The Clorox product you want to use is simply called "Clorox Disinfecting Bleach".

If you need help figuring out the proper amount of bleach to use for your tank, check out a chlorine dilution calculator like this one: https://www.publichealthontario.ca/en/h ... calculator

Smooth sailing,

Jim

[Bob Ohler]

This is what I was looking for.

Thanks Jim!

[Carl Thunberg]

Thanks, Jim. I've been adding too much bleach. My bleach is 7.5%. At 2% for a 50-gallon tank, I'm getting 1 teaspoon. That doesn't seem like very much, but that's what the calculator tells me.

[gonesail]

i've been using STAR BRITE Aqua Water Treatment & Freshener. it took about a month for it to work but things are good now and I use it at every fillup.

[Tom Keevil]

We treat our water system with a heavy dose of bleach every spring, and then leave it alone. We reason that we are filling the clean tanks with potable water from a municipal system, so it shouldn’t need anything else.

The spring treatment is 1/2 cup bleach in a 20 gallon tank, fill with water and sit for an hour. Then pump it all out through the system (don’t overheat your pump). Refill the tanks and pump it all out again. Refill again and you’re probably good to go. If the taste is still too much, do another rinse.

We’ve done this for 20 years with success. I should also mention that we fill our tanks directly, not from the deck fills. I’m not at all confident of what might be living in those deck fill hoses.

[wikakaru]

Thanks, Jim. I've been adding too much bleach. My bleach is 7.5%. At 2% for a 50-gallon tank, I'm getting 1 teaspoon. That doesn't seem like very much, but that's what the calculator tells me.

That sounds about right. Other people have mentioned much higher concentrations, but it sounds like they are talking about "shocking" or cleaning the tank rather than maintaining the water quality throughout the season in a clean tank. You would not want to drink the water at those higher concentrations, you would first drain the tank and re-fill it, then treat at the low concentration. As the chlorine works its concentration drops, so you need to add bleach periodically even if you haven't used or refilled the tank. How often you need to do this depends on what's growing in your tank and how often you use it. A rough guess is you might add a teaspoon once a week or every time you fill up, whichever comes first. Use the sniff test. If you can't smell chlorine any more, add a teaspoon.

Smooth sailing,

Jim