Water Chlorination - How Much?

[S/V Illusion]

Originally Posted by colemj

Reality check here.

Adding bleach (sodium hypochlorite) to an aluminum tank is not going to release chlorine gas or any other poisonous gas.

Mark

Absolutely correct! Many of these comments are misleading.
Re: Chlorine test kits - there are many types and their quality varies significantly. Buying a "cheap" test kit is simply bad advice on which to reply for your health.
Re: Peroxide - is safer, more effective and has a longer retention time (read - longer effective life) than chlorine solutions but can be hard to find in concentration which make it effective. Typical drug store bought peroxide is useless in this application. The proper mixing ratio for peroxide is obviously a function of it's concentration so without knowing what someone can obtain, making generic statements regarding mixing is misleading.
Aluminum interaction - does occur but more so when shocking the tank(s).
So-called charcoal filters - these carbon filters are more a feel-good device then anything effective, particularly for removing chlorine and most organics which they don't do well. The efficacy of carbon is dependent entirely in residence time, i.e., the time during which the water is in contact with the activated carbon, and as may be intuitive based simply on size, running water at a high rate through these very small cartridges makes the actual residence time FAR too small to be effective.

None of this is top say one should not attempt to maintain clean potable water but keeping it fresh rather than stagnant does more than you may ever accomplish with some of these recipes quoted elsewhere.

[sailorboy1]

Knew I didn't want to get involved in this because the "experts" would come out! Now there are all kinds of disclaimers aganist things that weren't even said!

You guys have at it. I'm going to work on my resume because after all these years I must not know anything about water and chemical treatment and must be about to get fired!

[S/V Illusion]

Sorry if I offended you by trying to be helpful. There are a few of us who actually do this as a profession.

[Tellie]

Mark,
The charcoal filter is important to your watermaker, don't be penny wise and pound foolish here. (Removed as not to offend the sensitive) Pass on adding any bleach. I've seen plenty of water tanks and they ALL have funky stuff in them. Two things, a good under the galley filtration system is your best defense from the tank funkies. Second, when you get the chance every now and then just add dock water to your tanks. That will help a little in keeping the tanks clean longer. Also from experiance, practically everyone eventually has a tank go bad no matter how anal they are.

[CarlF]

I can attest that the danger to tanks from chlorine is real. My current approach has been to do a twice a year "shock" with chlorine (8 oz bleach per 20 gal of tank left to sit for 12 hours - including in all hoses). I then do multiple flushes of the tanks to clean out the chlorine. My theory is that this is less corrosive than leaving chlorinated water in the tanks all the time.

I have then installed a under-sink water filter and a separate UV water purifier with hoses to a drinking water spigot at each sink. These UV filters have dropped in price. My 2 gal/minute unit was $150. It draws 16 watts. Beside the water spigots, I also plumbed a "return" hose after the UV filter back to the water tank (with a valve). This way I can circulate the tank water at about 1 gal/minute through the filter and UV purifier. Once a week, I let it circulate enough to cycle the tank water three times over. I also run the water maker product water through the UV filter. To save power, I only turn on the UV filter's light when I am circulating, making water, or am trying to impress a guest who wants to bring those damn plastic water bottles on board.

My theory is that this is like using the water and replacing with fresh since the water being circulated back to the tank after the UV light is supposed to have nothing growing in it.

This is a "home grown" solution that has seemed to work but I'd love comments.

Carl

[lorenzo b]

I do believe you'all getting a little carried away here. Little green things growing in the water will not harm you, any more than a salad will. What will harm you are specific bacteria that cause some very ugly diseases, but it is very unlikely they will find their way into an isolated water supply system on a boat. If they do, your gut will let you know and you can treat the problem easily.

[sailorboy1]

Originally Posted by S/V Illusion

Sorry if I offended you by trying to be helpful. There are a few of us who actually do this as a profession.

do what?

[Tellie]

Originally Posted by CarlF

I have then installed a under-sink water filter and a separate UV water purifier with hoses to a drinking water spigot at each sink. These UV filters have dropped in price. My 2 gal/minute unit was $150. It draws 16 watts. Beside the water spigots, I also plumbed a "return" hose after the UV filter back to the water tank (with a valve). This way I can circulate the tank water at about 1 gal/minute through the filter and UV purifier. Once a week, I let it circulate enough to cycle the tank water three times over. I also run the water maker product water through the UV filter. To save power, I only turn on the UV filter's light when I am circulating, making water, or am trying to impress a guest who wants to bring those damn plastic water bottles on board.

My theory is that this is like using the water and replacing with fresh since the water being circulated back to the tank after the UV light is supposed to have nothing growing in it.

This is a "home grown" solution that has seemed to work but I'd love comments.

Carl

I like it. A fresh water polishing system. Makes sense.

[markpj23]

Originally Posted by Hud3

....Careful with your dosage, though. Unless you want a blond wife!

Hee hee - got that already and this approach may add to the cruising kitty since there will be fewer trips to the beauty supply store...

Geez - I'm sorry I asked now. Guess it's just fresh water washdown time followed by a dockside hose into the tank now and then. I have the undersink filters for drinking anyway. Was just trying to head off skunky water.

Many thanks for the replies everyone....

[sailorboy1]

UV is a common and effective disinfection method. Used a lot in water and waste water treatment plants.

I don't feel you really are getting much from doing the recirulation to the tank. Biological doesn't really like to be free in the water and instead always forms into bio-films. The UV of course only treats what is floating in the water (the part that "bugs" us from the tap). So if you have bio problem in the tanks so are going to have to go after the bio-film somehow (chemical or mechanical cleaning). I'm not saying the recir is a bad thing, just that it's not doing anywhere near as much good as you would think as itdoesn't nothing to a bio-film (and the bio-film isn't necessay bad for you).

On the peroxide: never suggested going to drug store and getting the stuff. That is pretty diluted (the 1 in my house says 3% and I expected it to be less). Get the industrial 35% (which means it's still 65% water). BUT if you did use the store struff and added enough it would work. If using the 35% peroxide, add 1/10-gal for 100-gal of water. If you did buy the 3% stuff from a drug store, well add 1-gal (this is a total tank disinfection where you're going to flush after).

Same thing on bleach; doesn't matter the concentration just how much free chlorine you get into the system beyound what is consumed by the bugs. Which is why you need something to test for it. Saying buying a "cheap" test kit to protect your health is useless (the tester I use out in the field is $1400 if anyone wants to buy 1 let me know) is crazy; are you saying it is better for your health to guess instead.

[Hud3]

We used a General Ecology Seagull IV filter on the boat for the water that we drank or used in food that wasn't cooked. It was hard to determine the provenance of the water we took on at various places in the eastern Caribbean. The Seagull filters out bacteria, cysts and viruses and also has an activated carbon layer for organics, taste and smell. US EPA certified. We have one here in Nevis in our kitchen for the same purpose, since we use rainwater collected off our roof into a cistern.

[barnakiel]

Why not make less water and NOT chlorinate it ???

barnie

[Laidback]

Chlorination of Drinking Water

[Therapy]

Originally Posted by Laidback

Chlorination of Drinking Water

Too much work.

I am just going to drink it till it smells too bad or I get sick.

[sailorboy1]

Just a note about the filters etc. Most are based on household water that has chlorine it them and therefore are getting biological treated all the time. In my industrial water treatment experience it is very common for the filters to become a BIG biological problem as they collect "stuff" (the smell when opening chases you out if the room, but the water itself looks fine). I would still install (and plan to install on my boat as it's on this years project list) these filter systems. But you should plan to replace them much more often that what it might say on the package.