CYA reduction success

[csrpenfab]

Just about two weeks into seeing the TFP light, and my water is now near perfect! Long story short, thanks to my PB installing a tablet feeder and the idiots at Leslie's, my water looked like this two weeks ago:

FC - 4.6
pH - 7.2
TA - 32
CH - 350
CYA - 160

As a result, the TFP app was telling me I needed at least a gallon of bleach daily. Time for a drain and refill! Due to hot weather and HOA nazi's, I did my 2 drain/refills in the evening and refilled overnight.

Results this morning looked much better:

FC - 6.8
pH - 7.4
TA - 80
CH - 270
CYA - 60

I only had to add 4 oz. of bleach after my refill. My CYA is now at 60, should I do another small drain or leave it alone? Pool gets lots of sun here in So. CA. Thanks again for all the help. Now I won't be buying 6 gallons of bleach weekly!

 

[Oly]

Only 4oz? Maybe 40oz?
Looks good and I would not mess with a 60ppm CYA now. Roll through the winter months and check it again in the spring. What is important is the amount of FC loss in 24 hours as this determines your sanitation costs. Once you have your FC in the target zone relative to your CYA and your 24 hr FC loss is minimized, you are adding the same daily rate average to keep it there if everything is normal. If FC loss starts to get above 2ppm then test overnight and you determine if your loss is due to bio-load or sunlight degradation. All bets are off if you get behind on your sanitation and you experience an algae bloom then the higher CYA concentration will demand a much higher SLAM FC level and in very high CYA situations a successful SLAM may be impossible.

 

[csrpenfab]

Only 4oz? Maybe 40oz?
Looks good and I would not mess with a 60ppm CYA now. Roll through the winter months and check it again in the spring. What is important is the amount of FC loss in 24 hours as this determines your sanitation costs. Once you have your FC in the target zone relative to your CYA and your 24 hr FC loss is minimized, you are adding the same daily rate average to keep it there if everything is normal. If FC loss starts to get above 2ppm then test overnight and you determine if your loss is due to bio-load or sunlight degradation. All bets are off if you get behind on your sanitation and you experience an algae bloom then the higher CYA concentration will demand a much higher SLAM FC level and in very high CYA situations a successful SLAM may be impossible.

thanks. I'll leave the CYA alone for now. Only 4 oz of CL called for today to hit my 7.0 target with CYA of 60.

 

[Oly]

So 4oz of Cl to go from 6.8 to 7ppm FC? That would make sense depending on how many gallons in your pool and the % chlorine you have.

Next figure out what your FC loss is after 24 hours for a normal late summer day.

 

[csrpenfab]

It was 4.1 oz. of 10% CL to go from 6.8 to my target of 7.0 in my 16,000 gallon pool. Just finished a long swim and the water was perfect. Nice and cool from the refill!

 

[mknauss]

I would suggest you use your Target FC from the [FC/CYA][/FC/CYA] as your minimum you see each day. Add enough chlorine to get to 7 + daily FC loss at the time you test and dose. So if your daily loss is 2 ppm FC, add chlorine to get to 9 ppm at the time you dose.

That leaves you a small buffer down to your minimum FC in case of a duck invasion or some other unusual organic event.

Take care.