Sanitizing fresh water tank

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Travelingelk

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I have been reading that Calcium Hypochlorite is better to use than bleach because it has no expiration you use so very little of the granules. Here is the rub: None of the articles explain the ratio of Calcium Hypochlorite to water to use. The only information I can find doesn't explain how to use in an RV fresh water system. Any help would be appreciated.
 

Henry J Fate

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A mixture equivalent to shocking a swimming pool is adequate. 25 ppm. Let it sit overnight. You can use more but will need to be sure to flush everything out well and multiple times.
 

UTTransplant

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A bottle of bleach is under $2.00. You use 1/4c per 15 gallons of fresh water. Hard to think calcium hypochlorite is less expensive.
 

Matt_C

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If where you live has city water, don't bother too much.  It will have significant residual chlorine.  If you can taste or smell it, it does.  Flush the system with that a few times and it will be as good as anything else..

That residual chlorine is a federal requirement and it is there in case there is accidental infiltration to the municipal system.   

Matt
 

1PlasticMan1

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What is the current thinking regarding the amount of bleach per 20 gallons of fresh water?  Also, an RV supply store told me that bleach is a carcinogenic.  Anybody want to comment on that?
 

1PlasticMan1

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Just answered my own question - See the statement below:
Is bleach carcinogenic?

Bleach is not classified as a carcinogen. The International Agency for Research on Cancer, has ruled that evidence is not sufficient to definitively classify it as carcinogenic or noncarcinogenic, although studies in animals have found that it has no carcinogenic activity.

Would still like to know the current ratio recommended per 20 gallons of water.
 

UTTransplant

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1PlasticMan1 said:
What is the current thinking regarding the amount of bleach per 20 gallons of fresh water?  Also, an RV supply store told me that bleach is a carcinogenic.  Anybody want to comment on that?
You can do the math for the quantity, but it comes out to about .3 c. And if chlorine is a carcinogen, there are black helicopters flying Al Queda leaders into Washington with the full support of the Armed Forces for a coup. (Heavy sarcasm) Chlorine is used in pretty much all public water supplies and in lots of private water supplies. Bleach (the cheap stuff) is just a weak solution of sodium hypochlorite, a pretty stable version of chlorine. I think I would go to another RV supply shop if they feed you such lies to sell their own products. It wasn?t a Camping World, was it?

As a former chemist, chlorine gas is a killer, and a chlorine salt in solution (sodium hypochlorite) can burn if it gets on the skin. Add the bleach to the water, not the water to the bleach. That provides dilution immediately.
 

Gary RV_Wizard

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Chlorine bleach (sodium hyprochlorite) gets picked on a lot these days but it's simple paranoia.  There is no credible evidence at all that chlorine is harmful in the recommended quantities.

As for calcium vs sodium hypochlrite, it makes little of no difference where the free chlorine ions come from.  Calcium hypochlorite is sold in bulk at local stores cause it is used in swimming pools, so if you needed 25-50 lbs it is a convenient choice. However, sanitizing an RV water system needs only a cup or two of liquid bleach, so a quart bottle from the local dollar store is plenty. Calcium hypo is more stable than sodium hypo, especially in sunlight, but you aren't storing water when you sanitize and RV.

I don't agree with much of the premise of this article (calcium hypochlorite is superior to sodium hypochorite), but it has instructions for using it to make water for drinking. Use double or triple the amount to sanitize a system that may have been contaminated.

Someone already said that the instructions for a pool "shock treatment" can be used as well. That's good advice, "shock" is just a swimming pool term for "sanitize".
http://survivaltopics.com/better-than-bleach-use-calcium-hypochlorite-to-disinfect-water/
 

Isaac-1

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Also when buying bleach look at the strength and also the age,  date code will be on the packaging for all but the cheapest stuff.  The cheap stuff is often 1% or 3%, brand name is generally 6% though 8.25% "concentrated" bleach has been getting very popular these day.  You also want plain bleach, not scented, not outdoor which has detergent, not "easy pour" which has thickeners.  Bleach looses strength with age, so you want to make sure the manufacture date is sometime in the previous few months, if possible, and not something that has been sitting on the shelf for years.

As to the exact amount to use, sanitizing with bleach is a function of concentration plus exposure time, most things are killed by very short contact times with moderate strength bleach, 1 ppm of chlorine will kill most stuff within a minute or two of contact.  There are however exceptions, things that create bio-films for one, as the bio-film creates a protective barrier, though these generally succumb to a sustained 2-3 ppm solution of chlorine within a few hours.  The real problem are highly chlorine resistant things like Giardia and Cryptosporidium these hard shelled parasites are highly resistant to Chlorine, as it takes Chlorine in the 50 ppm range several hours (around 8 ) to kill Cryptosporidium (20 ppm chlorine will also kill it, but takes about 2.5 days of contact).  Of course Giardia and Cryptosporidium should only be an issue if you connect to contaminated water sources.

Now for the simple answer 8 ounces of 8.25% bleach in 100 gallons of water results in about a 50 ppm Chlorine solution.

Personally if dealing with a known Giardia or Cryptosporidium contamination I might use Chlorine Dioxide not bleach to decontaminate, as it is far more effective against these organisms, though it is also far more expensive.
 

ChasA

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Plastic man,
Use 1/4 cup (2 ounces) of bleach for each 15 gallons of water. Fill your fresh water tank and then run every faucet until you can smell the bleach. Then let it all sit for 4 hours or more.
 

wackymac

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Bleach is not classified as a carcinogen. The International Agency for Research on Cancer, has ruled that evidence is not sufficient to definitively classify it as carcinogenic or noncarcinogenic, although studies in animals have found that it has no carcinogenic activity.

It's probably on California's Prop 65 list.
 

Mark_K5LXP

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Missing from the black helicopter premise of cancer causing concentration, the bleach solution is used to sanitize then is flushed out.  So the only agent remaining is whatever few ounces of residual solution there is in the tank, then diluted again into another entire tank of water.  Parts per billion perhaps.

Mark B.
Albuquerque, NM
 
 

1PlasticMan1

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Thanks to you all for your response. Numbers match pretty much what I have been using since I got the coach, except the first time, when I used a little too much and bleached my wife's hair.  Boy oh boy did I get in deep dodo on that one!  You'd think after 55 years of marriage, she would get used to it!  UTTraveler, surprisingly, it was not Camping World, but a long well established RV dealer. 
 

mel s

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UTTransplant said:
A bottle of bleach is under $2.00. You use 1/4c per 15 gallons of fresh water. Hard to think calcium hypochlorite is less expensive.
I've sanitized my fresh water system TWICE, (once in 2001 and again in 2015).
Both times with a bleach solution. https://www.youtube.com/watch?v=RfPKYd_AVk8
 

NY_Dutch

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wackymac said:
Bleach is not classified as a carcinogen. The International Agency for Research on Cancer, has ruled that evidence is not sufficient to definitively classify it as carcinogenic or noncarcinogenic, although studies in animals have found that it has no carcinogenic activity.

It's probably on California's Prop 65 list.

It's not:

https://oehha.ca.gov/media/downloads/proposition-65//p65list030819.pdf
 

Rugger334

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Most Clorox containers show the dilution.  I used Clorox mildew, as I am re modeling my camper and the tank had been sitting for a while.  I went by the instructions on the bottle, let it sit all day while I worked...drained it, rinsed it...did it a second time (mainly bc the tank had been sitting a long time), not as concentrated.  Good to go.  I think it was $8 for Clorox mildew specific bleach from Home depot and instructions like most things on the bottle.

https://www.clorox.com/products/clorox-germicidal-bleach-concentrated/unscented/
 

darsben

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Rugger334 said:
Most Clorox containers show the dilution.  I used Clorox mildew, as I am re modeling my camper and the tank had been sitting for a while.  I went by the instructions on the bottle, let it sit all day while I worked...drained it, rinsed it...did it a second time (mainly bc the tank had been sitting a long time), not as concentrated.  Good to go.  I think it was $8 for Clorox mildew specific bleach from Home depot and instructions like most things on the bottle.

https://www.clorox.com/products/clorox-germicidal-bleach-concentrated/unscented/
Why not just double the amount of bleach? All bleach is germicidal and will kill even the AIDS virus. We do not need to reinvent/modify the use of bleach as a sanitizer just use plain bleach. Any fancy stuff is a waste of money
 
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