Dilutoing 12.5% Liquid Chlorine for Storage

[Pool Amateur]

I have bought 12.5 % liquid chlorine. If I dilute it myself with water to 6%, will it be the same half life as store bought 6%?

 

[chem geek]

Yes, but only if you dilute with water free of metals since they catalyze the decomposition.

 

[Pool Amateur]

Thank you Chem Geek, Is most tap water from a township suitable or should I use distilled? Will have to see if I use distilled might be more economical to by bleach at 8.5% or 6% at the store. I was using chlorinator with trichlor and was surprised how quickly CYA was rising. So I am going to use Liquid chlorine when possible. Still have a lot of tuning but this web site is a great asset.

 

[JoyfulNoise]

This PDF is a good primer on hypochlorite decomposition.

You should probably use distilled water just to be safe. However, a bigger problem may be pH rather than metals. The hypochlorite decomposition rate is slowest at high pH. Commercial bleach has excess lye in it which is why bleach tends to increase pH when you add it to pool water. If you cut the commercial grade stuff you have in half with distilled water, you could drop the pH of the resulting mixture making the decomposition rate faster.


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[chem geek]

It should be OK since the pH would only drop by 0.3 units and that's less than what is done with lower concentration hypochlorite solutions anyway. That is, 12.5% chlorinating liquid is typically a pH of 12.5 (for high-quality) while 6% bleach is usually around a pH of 11.9. The excess lye amount varies as the square of the concentration for its optimal amount.

 

[Pool Amateur]

Thanks a lot that really helps, I am going to try and rig up a temp, inexpensive, semi automated delivery pump or system that I can monitor 3-4 times per week to get me through the next 2 months, then close pool and make some larger decisions on the upgrades I need to do for next season.