Adding Bleach to RO Water

[sailorboy1]

So 25 years of water treatment experience and training tells me to maintain a small free chlorine level in my water system. This is easy when filling the tanks from city water, but now I am using my watermaker.

Yes there is a carbon filter in the wm flush system to remove chlorine as we know that kills the membrane. I long ago installed a small standard carbon drinking water filter as i used to maintain a fairly high chlorine level because that water would be in the tanks a long time. I know for a fact via testing that it removed the chlorine, but if not all it effected really was taste.

So for cruisers using RO, are you adding a little bleach etc. to your water tanks, which course gets used for RO flushing later?

And yes I understand some make extra water in a bucket and then use that.

[Training Wheels]

I put bleach in my tank about once a month. I do not like green water tanks!

[Chotu]

Watermaker, no watermaker, I always use chlorine in my tanks (boat, RV, whatever).

Your instincts are right. Keeps it fresh and free of algae

[SailFastTri]

For those who add bleach - what concentration is appropriate?

[tkeithlu]

"To disinfect a storage tank or other large volume of water, thoroughly mix non-scented NSF-approved household bleach (5.25% chlorine) in the reservoir at the ratio of 1 gallon of bleach for every 1,000 gallons of water (i.e., 1 quart for every 250 gallons of water). This will give a chlorine concentration of 50 ppm."

Compliments of the State of Idaho.

[Chotu]

Since I have been doing this for decades, I distilled it down into something easier to remember.

I use two heaping capfuls from a standard Clorox bottle per 50 gallons. Easy to remember. You’ll never forget. It’s also the right proportion if you do all the math.

In addition to watching out for scented bleach products, watch out for the no splash bleach. It’s filled with surfactants which are not good for you. You can only use traditional regular bleach.

[sailorboy1]

I think i wasn't clear . The question is about adding bleach to your water tanks then using that water through your watermaker carbon filter to flush the watermaker after use or as needed.

[Pillroller]

Water for Water maker. Whatever you put in your drinking water is fine, you will soon taste it if over done. Putting bleach into feed water for a water maker DO NOT. Bleach has a high pH to stop the Chlorine disappearing. Membranes do not like it.
Consult your manual of instructions, before doing ant additions to sea water.

[jmschmidt]

How do you "heap" liquid in a cap, or a swimming pool for that matter?

[vanderd]

I have pondered the same question for quite a while. We live in Florida where the warm temperatures necessitate chlorine in the city water. Just for kicks one day I tested the tapwater and compared to our pool water. The chlorine levels were similar.Knowing this I’m not too concerned about a small quantity of chlorine in my tank water. However, I change my charcoal filter more often than is recommended by the manufacturer.

[brendanwalls]

When I bought my boat 5 years ago I was advised to put alcohol in the water tanks to prevent freezing, and so I put a litre of Polish Spirit 100% alcohol in my 12 gallon water tank, which I only use for cleaning purposes. It always smells good even after 5 years of using and topping up, so I assume no algae.

[Chotu]

Originally Posted by sailorboy1

I think i wasn't clear . The question is about adding bleach to your water tanks then using that water through your watermaker carbon filter to flush the watermaker after use or as needed.

As long as you are absolutely sure that carbon filter is working perfectly. Because chlorine is not supposed to be good for the membrane. That’s why you don’t use tapwater to backflush. Ideally, the product water is the best thing for a backflush. Without any additives. But as long as that charcoal filter is really working, you should be good to go.

[Chotu]

Originally Posted by jmschmidt

How do you "heap" liquid in a cap, or in a swimming pool for that matter?

Same way you do with a teaspoon of sugar.Nice and generous. A little bit might fall out. That’s the Way to go. Surprised I have to explain that. But, it is what it is I guess. Lost in translation.

[CarlF]

People are giving the large amounts of bleach you use to sanitize a dirty tank. A clean tank using RO water requires just a tiny fraction of this (RO water has no bacteria when it enters the tank as the membrane stops it)

Here's my formula: 1 tablespoon of household beach (5.25% chlorine) will treat 100 gallons of water to 2ppm. Municipal water is 1ppm. Pool water is 3-5ppm. I treat my tank to 1ppm. This has no chlorine smell and hardly any taste even before running it through a final filter. 3ppm smells and tastes like pool water. https://www.publichealthontario.ca/e...ion-calculator

As to the watermaker water - chlorine typically mostly dissipates within 24 hours in water that is open to air. The tank vent allows that to happen. I try not to flush the watermaker within 2 days of adding bleach and assume the chlorine is then long gone. Although I still use a chlorine filter on the flush and ALWAYS replace it every six months as it become ineffective after that -- even if not used much.

Make sure your bleach if fresh - it loses potency in less than a year in the jug. I bought a 1lb canister of Sodium Dichlor meant for hot tub sanitizing. This is an easy to handle crystalized chlorine source that works as well beach. 1/4 teaspoon per 100 gallons is all I use.

Finally, buy a $10 pack of pool test strips. This will tell you the tank chlorine level in PPM. You can test that it's 0ppm before a flush. And if you add bleach but it's back to 0ppm in three hours, you probably have some growth in your tank that's using up the chlorine. Add more chlorine to kill it.

[Timethief]

Originally Posted by jmschmidt

How do you "heap" liquid in a cap, or in a swimming pool for that matter?

Originally Posted by Chotu

Same way you do with a teaspoon of sugar.Nice and generous. A little bit might fall out. That’s the Way to go. Surprised I have to explain that. But, it is what it is I guess. Lost in translation.

I am going to presume he is using powdered Chlorine, not liquid.