Keeping CL at optimal levels during the winter

[GeneS]

I am keeping my pool open for the winter here in SC. The previous owner told me the SWG will not produce CL when the water temps dip below 60. What is the best way to at clorine using the BBB method since I have no way to maintain a constant supply of CL? I really do not want to add tabs like he did but will if I have to. Do I just add bleach as needed and test frequently?

Thanks,
Gene

 

[jblizzle]

The easiest is to just add bleach. Although when the water is that cold, the chlorine will not be consumed very quickly. You will have to experiment, but you may only need to test and add once a week ... and if you have a cover, maybe less than that.

 

[GeneS]

Thanks for the input. I assumed this was the case thanks for the reassurance. I really love not being tied to the pool stores since visiting this site and learning so much over the past few months.

 

[Billrector]

The easiest is to just add bleach. Although when the water is that cold, the chlorine will not be consumed very quickly. You will have to experiment, but you may only need to test and add once a week ... and if you have a cover, maybe less than that.

Could you please elaborate on this? After reading lots of posts on this site, I was under the impression that FC consumption had much more to do with sunlight (UV) than anything else including air and water temperatures. I do understand that algae is much more likely at higher water temperatures, but if no algae is present, then the water temperature is really not a factor. If all this is true, then I would assume that the only reason that less FC is consumed in the winter is due to the fact that the days are shorter?

 

[jblizzle]

There is always some amount of organics/algae in the water that is being killed and oxidized. The colder water slows any growth down significantly. But, you are also correct that the shorter days and less intense sunlight also contribute to the reduced FC consumption.

 

[chem geek]

It's both. If my pool is covered by the opaque cover all the time, I still lose around 0.7 ppm FC per day at 88ºF and this is temperature dependent. It's mostly chlorine oxidizing the cover, some chlorine oxidizing CYA, and the rest oxidizing anything else it can find in the water or elsewhere. This loss is very temperature dependent and slows to around a 1 ppm FC loss every 1-2 weeks when the water temp gets to 50ºF or so.

You can readily distinguish between the loss from sunlight vs. the temperature dependent loss by measuring the loss overnight when there is no sun on the pool. And yes, during the winter the loss from sunlight drops not because of temperature but because of the lower angle of the sun and usually having cloudier days.