liquid chlorine degradation


LifeTime Supporter
Feb 2, 2014
Houston TX
I have done some forum searches on the subject & realize liquid sodium hypochlorite will degrade over time & at higher temperatures & sun exposure

So having considered all that is it a better idea to go with a 15gallon tank or 30 gallon tank on a Stenner pump install ?

This will be sitting outside by the pool equipment & will get some early morning sun but be in the shade of the house most of the day yet still exposed to
90+ summer ambient air temps

I like the idea of a 30gallon tank for fewer trips to the chlorine store but if it degrades too much over that time frame I'll get the 15 gallon tank

I'll be using 10% liquid chlorine



TFP Expert
LifeTime Supporter
May 3, 2007
Pleasanton, CA
Pool Size
Salt Water Generator
Or you could go with a 30 gallon tank diluted by 50%. It may not use as much chlorine as the 15 gallon without dilution since the degradation of chlorine is also dependent on concentration.


Well-known member
Jun 22, 2013
East TN
How about a 30 gallon tank, 50% chlorine, 50% water from your pool. That will give your chlorine tank a CYA level half of what your pool is and wont add any CYA. That will only help from the UV rays. Put a fan on it or build a top to go over it to shade it all day. My bleach sits outside in a building that gets hot and I dont notice any percentage loss before the bleach gets used up but mine gets used in about 2 weeks maximum.

Looks like a 30 gallon tank of 50-50 will last you anywhere from 22 to 32 days with FC loss of 3 and 2ppm per day. That gives you 5% liquid chlorine and according to this chart you dont have anything to worry about. The UV rays will probably eat it up faster than the heat, but thats where the pool water comes in.

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
San Rafael, CA USA
If you dilute, you should use water with NO metals, not even trace amounts. Distilled or deionized water would be best, but if you are sure your tap water has virtually no metals then that would be OK. As noted in this link, metals such as iron, copper, cobalt, nickel, zinc, and other hevay metals will rapidly degrade concentrated chlorine.
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