Chlorine usage high. Again

[PoolNewb2020]

Why not perform another OCLT test? A month is a long time.

 

[A_kraker99]

OP, can you confirm that you are working with a true 12.5% CL? Even CL a month old stored indoors can loose potency.

I don't know how to confirm that. I have done a FC test before and after adding a measured dosage and verified the FC increase was on par with what Pool Math says it should be. The chlorine does sit in a translucent Pentair dosing tank throughout the week (4 gallon capacity) and it is exposed to sun. Not sure how much that would affect the percentage.

 

[beautifulpool]

4 ppm per day is on the high side of normal. Many people on this forum report such losses. I have as much confidence as anyone can possibly have based the wisdom of this forum and my test results that my pool is quite healthy, yet I lose about 4 ppm of FC. My pool is fully exposed to the sun all day and naturally heats to the low 90s at times.

Higher CYA does not increase chlorine demand. It does adjust the target number upward, but that is a one-time addition. It actually reduces chlorine demand. For example, if you are at 30 CYA with a target of 3-6 FC, and lose three ppm per day, in a week you will have added 21 ppm. If you jump to 50 CYA and a target of 6-8, it's a one-time addition of 3 ppm, but if the daily UV loss drops to 2.5, you're 0.5 ppm ahead after only seven days. Make sense?

In my very limited experience, there are diminishing returns on chlorine protection and CYA. The difference of jumping from 30 to 40 in my pool was pretty noticeable, probably close to 1 ppm per day. The effects of jumping from 40 to 50 were far less obvious. As usual, it is a trial and error process.

 

[Chasarms]

I don't know how to confirm that. I have done a FC test before and after adding a measured dosage and verified the FC increase was on par with what Pool Math says it should be. The chlorine does sit in a translucent Pentair dosing tank throughout the week (4 gallon capacity) and it is exposed to sun. Not sure how much that would affect the percentage.

If the LC was fresh when poured into the tank, I seriously doubt you are seeing measurable degradation in seven days. I add three weeks of LC to my tank at a time and have not seen recordable declines in FC levels as the product ages, and I use 12.5% LC.

If you are testing FC before and after dosing and the numbers equate to pool math expectations, then it is not the LC product.

At some point after experimenting with your CYA target , you may just have to concede that it is your version of normal.

 

[JimMarshall]

I don't know how to confirm that. I have done a FC test before and after adding a measured dosage and verified the FC increase was on par with what Pool Math says it should be. The chlorine does sit in a translucent Pentair dosing tank throughout the week (4 gallon capacity) and it is exposed to sun. Not sure how much that would affect the percentage.

So you’re chlorinating via a dosing pump?

 

[A_kraker99]

So you’re chlorinating via a dosing pump?

Yes. twice a day about 7 minutes of runtime each time.

 

[JimMarshall]

Yes. twice a day about 7 minutes of runtime each time.

And how long does your pump run?

 

[A_kraker99]

And how long does your pump run?

I have a Intelliflo VS so I have variable speed settings throughout the day. I do about 2.5 pool turnovers per day. The pump is completely off from 11PM till 7AM.