What Is The Better CYA Level

[cleanpool]

Hello All
I am very anxious about my cya leve. I live in sc and it is usually very hot. The sun is on my pool all day,no shade until late in the evening. My question is should my cya level be at 50 or should I shoot for 30 or 40. Most folk say to shoot for 40,but I have noticed spots of algae over time. I use tf100 test kit. I have kept my cl at the target suggested by pool calculator for cya at 40. I use 6% bleach,WalMart brand. My last checks cl 5,ph7.6,ch50,ta70,cc0,cya35-40. I really do appreciate the help I always receive from all of you. God speed.

 

[Isaac-1]

I think 50 is a reasonable number to target given your full sun exposure in the south. The thing is you are sort of on a dividing line, if you were in FL with full sun I think everyone here would say your good at a CYA level of 50, where if you were in MA with the same condition they would say you were a bit high on CYA.

Ike

 

[jblizzle]

If you are seeing spots of algae, then your FC must not be high enough at all times.

Also, if it is ever visible, you should go through the shock process until you pass the 3 tests and then be sure the FC does not drop too much.

 

[RobbieH]

CYA is not going to help you with algae, that's a matter of FC and to an extent circulation. Can you be more specific about where your FC is before you make your additions, and where you are seeing algae?

 

[cleanpool]

My fc is never lower than 4 with cya at 40. The algae is just a very slight green only at 1 or 2 places at the top of the deep end slope. I was thinking if my cya is too low for the amount of sun exposure,even if my cya is at 40, this could cause too fast consumption of cl during the day. I know this makes no sense. I did shock,per calculator suggestion,and all algae disappeared. Thanks,Thanks.

 

[cleanpool]

I always use the fas/dpd to test cl usually at late evening.

 

[RobbieH]

If it was being consumed by the sun, it would drop to very low levels, not from 5 to 4.

Did you shock according to the shock process in Pool School, or did you use a shock product?

 

[cleanpool]

I shock only by the calculator suggestion and pool school. Always with great results. I have increased my cl from 5 to 6.I usually loose 2ppm most days. This is why I'm anxious. I don't want to ruin my liner with unnecessary high cl. THANKS THANKS

 

[RobbieH]

You won't hurt your liner all the way to shock level.

 

[cleanpool]

Great answer RobbieH. Thanks for reassurance. I'll stay on top of all checks. I think I'll stay with cya 40 to 50. Thanks again.

 

[jblizzle]

For that matter, you will not likely harm the liner unless you are above Mustard shock level (according to poolcalculator)

For CYA of 40ppm, that is 24ppm
For CYA of 50ppm, that is 29ppm