can I maintain lower FC in the winter when water temp is in the 30s 40s

[engrav]

Hi
The TFP method works well, have not had algae bloom for years.
Do not close in the winter and water goes down into the 30s.
CSI includes water temp and so adjusts for water temp but FC is not in the CSI.
I would like to think I can run FC much lower in the winter, save a little money.
Is there a page on the TFP web describing FC requirements in the winter with cold cold water?
Thanks
Loren

 

[ajw22]

You should run the same FC level but you will find the chlorine consumption will be lower and you will need to add LC less often.

 

[engrav]

You should run the same FC level but you will find the chlorine consumption will be lower and you will need to add LC less often.

ok, got it
my min is 3 and the target is 5-7
can I let the min go to 1 or 2 and the target to say 3-5
or
should I use the same min and target

CYA is 35

 

[ajw22]

ok, got it
my min is 3 and the target is 5-7
can I let the min go to 1 or 2 and the target to say 3-5
or
should I use the same min and target

CYA is 35

You don’t got it if you are asking that.

Maintain 5-7. You will need to add LC less often in the winter to keep FC above 5.

Your LC needs don’t change if you change your target.

 

[engrav]

You don’t got it if you are asking that.

Maintain 5-7. You will need to add LC less often in the winter to keep FC above 5.

Your LC needs don’t change if you change your target.

will try again
first question was what to do in the winter?
answer: do the same thing but will need to add less often
got it, that is what I did the past winter, added 1/2g chlorine every week or so
second question
if I need 5-7 in the summer when water temp is say 75 and algae are revved up
why do I need 5-7 in the winter when water 40 and algae are moribund
and/or
if FC3 works, why do FC5-7? (in the winter)

 

[ajw22]

if I need 5-7 in the summer when water temp is say 75 and algae are revved up
why do I need 5-7 in the winter when water 40 and algae are moribund
and/or
if FC3 works, why do FC5-7? (in the winter)

Because you have CYA 40 and most of your FC is bound to the CYA with a small amount of active chlorine. You need 5-7 due to the CYA 40, not because algae are revved up.

CYA - Further Reading

www.troublefreepool.com

 

[engrav]

Because you have CYA 40 and most of your FC is bound to the CYA with a small amount of active chlorine. You need 5-7 due to the CYA 40, not because algae are revved up.

CYA - Further Reading

www.troublefreepool.com

ah yes, active chlorine as opposed to free
so one more please (maybe the end)
say in the summer I have 5# of alert awake algae in the pool reproducing at 10 cell cycles / minute and say active chlorine 2ppm keeps 'em at bay
say in the winter I have 5# of algae but they are comatose, reproducing at 10 cell cycles / hour, do I still need 2ppm active chlorine to keep 'em at bay
thanks

 

[ajw22]

ah yes, active chlorine as opposed to free
so one more please (maybe the end)
say in the summer I have 5# of alert awake algae in the pool reproducing at 10 cell cycles / minute and say active chlorine 2ppm keeps 'em at bay
say in the winter I have 5# of algae but they are comatose, reproducing at 10 cell cycles / hour, do I still need 2ppm active chlorine to keep 'em at bay
thanks

I suggest you look at the beginning of Pool Water Chemistry

Active chlorine is less than 0.100 ppm.

 

[aeh0603]

Proper chlorine levels do not change when the temperature changes. If you maintain proper chlorine levels, you don't have algae reproducing in your pool. If you have visible algae in your pool, you need to perform a SLAM process to kill it.

In the summer more chlorine is consumed by the sun, so in the winter you don't need to add a much chlorine to maintain the same FC level. If your pool is open year round, your target FC is always based on the FC/CYA chart. FC target is not temperature dependant, it is CYA dependant.

 

[engrav]

thank you
I guess I fail at asking the question, I apologize for the lack of clarity

will try only one more time, promise

if algae are not actively dividing, do I need as much active chlorine as I do when the algae are actively dividing?

 

[wireform]

The simple answer is yes you do. The mere fact is that you will be adding very little to keep the same target is because it's not going to get consumed very fast. Cooler temps along with shorter days and the sun's angle all contribute to using less chlorine at the same target level.

 

[ajw22]

thank you
I guess I fail at asking the question, I apologize for the lack of clarity

will try only one more time, promise

if algae are not actively dividing, do I need as much active chlorine as I do when the algae are actively dividing?

How do you know that algae will stay dormant throughout the time period you have lower chlorine?

You want the active chlorine to be on standby at all times should the algae get active.

 

[aeh0603]

Yes, you do. There is more than just algae that can grow in water, bacteria and other organisms can grow too. Some of them grow better at cooler temperatures, so you need to maintain your FC at the same target to keep your water sanitary.

 

[engrav]

found an old thread on this topic

Algae and cool water

My pool water is 71*. I am adding 14oz of 10% bleach daily and maintaining FC of 2. My question is, at what temp will the possibility of algae stop and will I have to add chlorine even if the water is too cold for algae to grow? Thanks

www.troublefreepool.com

proving there is nothing new under the sun

 

[mknauss]

found an old thread on this topic

Algae and cool water

My pool water is 71*. I am adding 14oz of 10% bleach daily and maintaining FC of 2. My question is, at what temp will the possibility of algae stop and will I have to add chlorine even if the water is too cold for algae to grow? Thanks

www.troublefreepool.com

proving there is nothing new under the sun

The most important response in that thread is from ChemGeek

Though the growth rate of algae slows down as water gets colder, the reaction of chlorine killing algae also slows down. So lowering the FC level too much could be risky. The main advantage of the cooler water, especially if the sun isn't on the pool due to clouds or a cover, is the lower daily FC usage. I'd keep the FC at whatever level you normally need to do to prevent algae. Though it's possible that at some cold water temperature the algae growth plummets, why take the chance that it doesn't?

 

[engrav]

The most important response in that thread is from ChemGeek

true and I think that is the answer to question #2
the growth rate slows but the kill reaction also slows so tis a draw
my FC was 3.5 so I added some, temp is 52
thanks