# HTH Storage



## Davarm (Oct 22, 2011)

I have a question for those smarter than myself(should be quite a few of you).

I had a box of HTH on the shelf, set aside for water purification, and when I looked at it a few days ago it looked like someone had oiled the bottom half of the box. When I opened it and felt the packages they were soft and mushy, about the consistency of prepared cake frosting instead of being granular.

When I opened one of the packs, it was a white paste that only had a slight smell of chlorine, no chlorine smell was present before I opened the pack. The "oily substance" didn't appear to be corrosive or have an odor and only enough was present to coat the bottom of the box and leave a slight oily feel to the shelf where it sat.

The box had been on the shelf for about 4 years and I hadn't noticed the change until recently. It wasn't sitting in a place that I regularly look so I have no real idea of when the change occurred. I do know that where it was stored has an average temp of about 80 degrees, the humidity varies between about 40-60%, isn't stored in sunlight and the light(led) is on about half the time.

The individual packets were still sealed and nothing "oozed" out when I squeezed them so I'm sure they were still air tight.

The question I have is: Does HTH have a maximum shelf life and is it designed to "self destruct" after a certain period of time?


----------



## Moose33 (Jan 1, 2011)

Please forgive my ignorance, what is HTH?
Thank you,
Moose


----------



## Country Living (Dec 15, 2009)

Chlorine...


----------



## Marcus (May 13, 2012)

HTH is super-concentrated chlorine used in swimming pools. Preppers buy it for water purification purposes since it's cheap..

http://www.hth.co.uk/what-is-hth-calcium-hypochlorite

To answer your question, Davarm, I found this:
http://www.jed-drilling.com/files/8714/0475/5024/HTH_Dry_Chlorine_Granular.pdf

It's a MSDS put out by Arch Chemicals.

"SECTION 3 PRECAUTIONS FOR SAFE HANDLING AND STORAGE
DO NOT TAKE INTERNALLY. AVOID INHALATION OF DUST AND FUMES. AVOID
CONTACT WITH EYES, SKIN OR CLOTHING. UPON CONTACT WITH SKIN OR EYES,
WASH OFF WITH WATER. REMOVE AND WASH CONTAMINATED CLOTHING BEFORE
REUSE.
STORAGE CONDITIONS: Keep product tightly sealed in original containers.
Store product in a cool, dry, well-ventilated area. Store away from
combustible or flammable products. Keep product packaging clean and
free of all contamination, including, e.g., other pool treatment
products, acids, organic materials, nitrogen-containing compounds, dry
powder fire extinguishers (containing mono-ammonium phosphate),
oxidizers, all corrosive liquids, flammable or combustible materials,
etc.
DO NOT STORE AT TEMPERATURES ABOVE: 52 Deg.C (125 Deg.F)
Storage above this temperature may result in rapid decomposition,
evolution of chlorine gas and heat sufficient to ignite combustible
products.
PRODUCT STABILITY AND COMPATIBILITY
SHELF LIFE LIMITATIONS: Shelf life (that is, the period of time before the
product goes below stated label strength) is determined by storage
time and temperatures. Do not store product at temperatures above 52
Deg.C (125 Deg.F). When stored under moderate temperature
conditions, product will maintain stated label strength for
approximately two years. Prolonged storage at 35 Deg.C (95 Deg.F) or
above will significantly shorten the shelf life. Storage in a
climate-controlled storage area or building is recommended in those
areas where extremes of high temperature occur.
INCOMPATIBLE MATERIALS FOR PACKAGING: Product packaging must be clean
and free of contamination by other materials, including, e.g., other
pool treatment products, acids, organic materials, nitrogen-
containing compounds, dry powder fire extinguishers (containing mono-
ammonium phosphate), oxidizers, all corrosive liquids, flammable or
combustible materials, etc.
INCOMPATIBLE MATERIALS FOR STORAGE OR TRANSPORT: Do not allow product
to come in contact with other materials, including, e.g., other pool
treatment products, acids, organic materials, nitrogen-containing
compounds, dry powder fire extinguishers (containing mono-ammonium
phosphate), oxidizers, all corrosive liquids, flammable or
combustible materials, etc."

It looks like 2 years is the shelf life when stored below 95 degrees F.


----------



## Marcus (May 13, 2012)

It doesn't self destruct but rather it interacts with the outside atmosphere that leaks through the walls of the packaging.

Off hand, the only way I can think of to slow down this reaction is to store it in a sealed container and flush out the air with a noble gas. You can't use oxygen absorbers for this since it will react with the iron dust. Likewise, Nitrogen can't be used for the same reason. Since noble gases tend to be relatively expensive, you're probably better off just rotating your supply as it nears the end of its shelf life. If you go the noble gas route, I suggest Helium.

Another possibility may be to store the opened packets in lab glassware but I don't know that it would significantly raise the shelf life.


----------



## Grimm (Sep 5, 2012)

Marcus said:


> It doesn't self destruct but rather it interacts with the outside atmosphere that leaks through the walls of the packaging.
> 
> Off hand, the only way I can think of to slow down this reaction is to store it in a sealed container and flush out the air with a noble gas. You can't use oxygen absorbers for this since it will react with the iron dust. Likewise, Nitrogen can't be used for the same reason. Since noble gases tend to be relatively expensive, you're probably better off just rotating your supply as it nears the end of its shelf life. If you go the noble gas route, I suggest Helium.
> 
> Another possibility may be to store the opened packets in lab glassware but I don't know that it would significantly raise the shelf life.


What do you think of vacuum sealing it either in a jar or bag?


----------



## weedygarden (Apr 27, 2011)

Grimm, I have thought of canning jars. I think a problem would be the interaction with the metal in the lids. 

Mine is still in the original packaging, but I have wondered about good air tight options that would not lead to break down of the container and then the contents.


----------



## ZoomZoom (Dec 18, 2009)

I'm going to have to go check mine as it's past the 2-year shelf life.

If mine is also going bad, what's coming to mine is to just get new. It's the end of the pool season in many areas. Stores should have it on sale. Doesn't it cost something like $12 to do about a trillion gallons of water?


----------



## Country Living (Dec 15, 2009)

The bucket of chlorine tabs we use for the aerobic septic system (septic, not pool, grade) is starting to meld into one big weird looking tablet. I have to chisel them apart when I want to put a couple into the chlorine pipe. So far our water test from the third tank hasn't shown any cooties so I guess it's more cosmetic than anything.


----------



## Marcus (May 13, 2012)

Grimm said:


> What do you think of vacuum sealing it either in a jar or bag?


I'd go with a glass jar. I searched a bit more and found CALCIUM HYPOCHLORITE probably shouldn't be put in mylar either.

http://www.inchem.org/documents/icsc/icsc/eics0638.htm

Chemical dangers
Decomposes rapidly above 175°C . Decomposes rapidly on contact with acids. This produces chlorine and oxygen. This generates fire and explosion hazard. The substance is a strong oxidant. It reacts violently with combustible and reducing materials. The solution in water is a medium strong base. Reacts violently with ammonia, amines, nitrogen compounds and many other substances. This generates explosion hazard. *Attacks many metals.* This produces flammable/explosive gas (hydrogen - see ICSC 0001). *Attacks plastics.*


----------



## TheLazyL (Jun 5, 2012)

Chlorine in it's natural state is a gas.

Chlorine under pressure is a liquid at 100% strength.

Clorox bleach is 10% ish Chlorine suspended in a liquid solution.

HTH is chlorine in a dry form and is also about 10% strength..



Chlorine is VERY corrosive, will draw moisture from the air and is heavier then air. 

Clorox and HTH forms of chlorine will decay releasing the chlorine.

Are you on City water? If yes, fill a glass container will water and place in a refrigerator. A few hours later you will see bubbles on the side of the glass container. Those bubbles are chlorine escaping from the water. Tap the side of the container, chlorine will float to the top and escape into the atmosphere.


----------



## hiwall (Jun 15, 2012)

Just a warning that most here already know - if dry chlorine comes in contact with any kind of oil it will start a fire. Anyone who wants to test this just take a tab of HTH and add some brake fluid to it in a safe outdoor location. Then just stand back and wait for the fire to start. Fire fighters sometimes use this method in demonstrations.


----------



## Davarm (Oct 22, 2011)

weedygarden said:


> Grimm, I have thought of canning jars. I think a problem would be the interaction with the metal in the lids.
> 
> Mine is still in the original packaging, but I have wondered about good air tight options that would not lead to break down of the container and then the contents.


I have a lot to say about the replies so far but only a minute or two right now so will comment on the canning jars.

The first bag of HTH I opened was poured into a canning jar for storage, it went about 2 months before the lid was completely rusted through and the smell of chlorine flooded the bathroom I had it stored in.

After I played around with the stuff when I originally opened the first bag I used it in the bathroom for cleaning, hence the reason it was stored in the bathroom.


----------



## LincTex (Apr 1, 2011)

Are Tattler lids plastic? Maybe they can handle it.

Yes, the stuff is very hydrophilic. Sucks water (humidity) out of the air. 
Glass containers & old glass canning lids would be best. 

Stainless containers MIGHT work, depending - 
409 stainless - No friggin' way
316 stainless - Hmmm, maybe
321 stainless - that should work OK

I have mine stored in Gevalia Coffee containers (ceramic) with a bail holding the lid and what looks like a silicone rubber gasket.


----------



## LincTex (Apr 1, 2011)

Kilner Round Clip Top Green Jar 34-Fl Oz Green 34 Fluid Ounces

http://www.ebay.com/itm/Kilner-Round-Clip-Top-Green-Jar-34-Fl-Oz-Green-34-Fluid-Ounces/111751969636


----------

