I have been busy and let my pool go. It got lots of leaves in. When I finally got around to cleaning it, the water was green. It goes down to freezing here at night, then gets into the 40's in the day, so the water is pretty cold. I shocked it last night with what I calculated was the proper amount of bleach, but this morning the water is still green. Maybe I miscalculated something, but before I add more bleach, I would like to know if shocking works differently in cold water.
Does pool shocking work more slowly in cold weather?
- Thread starter TomAtlanta
- Start date
We do not shock our pools here at TFP. If you have algae, you need to follow the ShockLevelAndMAINTAIN Process 
This is not a one time chlorine addition as it appears that you have done. This process actually goes a little faster in colder water due to lower losses to the sun and the algae can not grow as fast.
This is not a one time chlorine addition as it appears that you have done. This process actually goes a little faster in colder water due to lower losses to the sun and the algae can not grow as fast.
This is sort of a related question so I'll ask here rather than starting a new thread.
Do you know if it effects the power of liquid bleach if it is kept in an unheated garage where it freezes and thaws, freezes and thaws, throughout the winter?
Do you know if it effects the power of liquid bleach if it is kept in an unheated garage where it freezes and thaws, freezes and thaws, throughout the winter?
While there is less chlorine loss at lower temperature and with the sun lower in the sky (or being overcast) and algae growth is much slower, all chemical reactions (including those involving chlorine) slow down at colder temperatures. At 40ºF such reactions will be around 8 times slower than at 80ºF so you can figure it will take a lot longer to bleach out the algae at the colder temperature.
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This post describes the freezing point depression for bleach and for acid. The freezing point depression for 6% Sodium Hypochlorite as found in the older Clorox Regular and most Ultra brands of bleach is 7.3C or 13.1F so the freezing point is -7.3C or 19F. The freezing point depression for 8.25% Sodium Hypochlorite as found in the new Clorox and other brand of bleach is 9.7C or 17.4F so the freezing point is -9.7C or 14.6F.
I do not think the bleach loses its strength due to freezing, but of course you have to be careful about having the bottle burst from expansion or develop cracks and then leak when thawed.
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This post describes the freezing point depression for bleach and for acid. The freezing point depression for 6% Sodium Hypochlorite as found in the older Clorox Regular and most Ultra brands of bleach is 7.3C or 13.1F so the freezing point is -7.3C or 19F. The freezing point depression for 8.25% Sodium Hypochlorite as found in the new Clorox and other brand of bleach is 9.7C or 17.4F so the freezing point is -9.7C or 14.6F.
I do not think the bleach loses its strength due to freezing, but of course you have to be careful about having the bottle burst from expansion or develop cracks and then leak when thawed.