FC and CYA high

[timmer21]

I have a new (1.5 years) Fiberglas pool. I had been using tricolor tablets until I found this site. I had been having a hard time keeping any measurable FC this past summer. I shocked the pool with powdered shock. Since then I had an acceptable FC level. I stopped using the chlorine pucks after I read the info on this site, but my chlorine is still high. I purchased the TF 100 test kit in late September and tested my pool. My FC was very high and ph was 6.8. The attached photo shows the high chlorine. I haven’t been able to test the water since the middle of October due to hip replacement and fracture. I tested again today and this is what I got:
FC. 26
CC 0
CH 250
TA 110
CYA 140 (using the half pool water, half tap water x 2)

These are the same results I had a month ago. The only thing that was added to the pool in that month was 5.5 inches of rain. The pool manufacturer says not to drain the pool or the warranty will be voided. Also the ground water in central Texas can cause the pool to come out of the ground. My pool does need water added at this point due to evaporation. Level is down about 3 inches from top of skimmer opening.
Any suggestions to drop the FC and raise the ph?

Thanks

 

[kul]

I have a new (1.5 years) Fiberglas pool. I had been using tricolor tablets until I found this site. I had been having a hard time keeping any measurable FC this past summer. I shocked the pool with powdered shock. Since then I had an acceptable FC level. I stopped using the chlorine pucks after I read the info on this site, but my chlorine is still high. I purchased the TF 100 test kit in late September and tested my pool. My FC was very high and ph was 6.8. The attached photo shows the high chlorine. I haven’t been able to test the water since the middle of October due to hip replacement and fracture. I tested again today and this is what I got:
FC. 26
CC 0
CH 250
TA 110
CYA 140 (using the half pool water, half tap water x 2)

These are the same results I had a month ago. The only thing that was added to the pool in that month was 5.5 inches of rain. The pool manufacturer says not to drain the pool or the warranty will be voided. Also the ground water in central Texas can cause the pool to come out of the ground. My pool does need water added at this point due to evaporation. Level is down about 3 inches from top of skimmer opening.
Any suggestions to drop the FC and raise the ph?

Thanks

Hmmm I’d wait to hear from one of the TFP EXPERTS, but I’m going to guess your FC is taking a while to come down because of the elevated CYA. Since a drain seems like it might not be a good choice for you, there is Reverse Osmosis and a water replacement option where you add water at the same rate you are removing water from a deep point in your pool. Interested to see what guidance is offered.

 

[mknauss]

Welcome to the forum!
With a CYA of 140, you should exchange about 2/3rds of your pool volume to get the CYA to 50 or so.
I suggest you read the Exchange section in Draining - Further Reading
I suggest you read ABC's of Pool Water Chemistry.

 

[march2012]

your FC will come down on its own over a few days. Just stop adding things to it. In texas we seem to lose CYA too so that may come down over time as well.

 

[Newdude]

Going forward with a 140 CYA (nice job on the dilution test, many miss that step ) will require a lot more chlorine to achieve the same sanitizing. In theory 3 ppm a day is 3 ppm a day but FC burns off at a faster rate at higher levels and you’ll blow through gallons and gallons trying to chase your tail.

You need to decide if you wish to fight the fight, or just drain 2/3+ like Marty suggested and make life a lot easier and cheaper in the long run. If you decide to exchange immediately, the PH will change so the current value is of less importance. If you either wait or dont drain, add Borax per pool math until the PH is in the 7s to save possible equipment damage. It may take many adds to bring it up enough as you don’t actually know the PH other than it’s below range. It might be a 5 and adding the amount to raise it from 6.8 might only raise it to 5.5, needing more adds.

 

[timmer21]

I did some more research on the draining water from my pool to get the CYA level lower. The Lathum pool warranty says that the pool level needs to be above the bottom of the skimmer to prevent any hydrostatic damage to the fiberglass shell. I will have to drain only small amounts at a time and refill to get CYA in an acceptable level to maintain my chemical balance. Thanks for all the responses.

 

[kul]

I will have to drain only small amounts at a time and refill

Ugh I’m sorry to hear this. So cumbersome!

 

[timmer21]

your FC will come down on its own over a few days. Just stop adding things to it. In texas we seem to lose CYA too so that may come down over time as well.

My FC has been high for over a month without adding any chlorine. During June and July I had a hard time keeping the FC above 0. I shocked the pool with powdered shock and since them, the FC has been high. I wasn’t able to accurately measure it until I got my new test kit.

 

[mknauss]

I will have to drain only small amounts at a time and refill to get CYA in an acceptable level to maintain my chemical balance.

Please read the Exchange portion of the article I linked above. The water level does not get lowered during an exchange.

If you wish to do as you say, that is fine. It will take about 10x as much water. If water is very cheap, go for it.

 

[reggiehammond]

Please read the articles that Mark posted; there's a no-drain water exchange option that's fairly easy this time of year.

Draining - Further Reading

www.troublefreepool.com

 

[timmer21]

Welcome to the forum!
With a CYA of 140, you should exchange about 2/3rds of your pool volume to get the CYA to 50 or so.
I suggest you read the Exchange section in Draining - Further Reading
I suggest you read ABC's of Pool Water Chemistry.

Thanks for the info on draining my pool. The water exchange method looks like what I need to do.

 

[timmer21]

Please read the articles that Mark posted; there's a no-drain water exchange option that's fairly easy this time of year.

Draining - Further Reading

www.troublefreepool.com

Just read it. Thanks