General CYA question

[babsh]

Should I keep my CYA on the higher side, its at 40 now, if my pool is in the sun ALL day? Or is the CYA number just relative to were you want to keep your chlorine number? I had CYA at 40 last year and it seemed like the 4 chlorine read didn't keep the algae away. I had to keep my chlorine at close to 6 most of the summer- so I was always adding chlorine. My thought was the 40 CYA wasn't "protecting " a 6 chlorine read. PH and TA were pretty much stable, they started wobble when there started to be an issue with algae.
Im leary of getting it too high because a few years ago, it was over 100! thanks to my pool supply store

 

[Pool_Medic]

7.5% of cya is minimum, 11%is target. With warmer water, higher bather loads and pollen I think 4 is to low. I would bump the cya up to 60 and keep my chlorine above 8 always.

 

[Oly]

Make sure you are in the CYA/FC zone. Pool School - Chlorine / CYA Chart
Keeping our FC at 4ppm with a CYA of 40 is on the low end and why you saw algae because during high demand it is easy to fall below your minimum.
When demand is high it's critical to keep your FC at the upper end of the zone to be safe. Test your FC in the early morning and after sunset for a few days to determine how much FC loss you have during the day vs the night. This will help you decide if you need to bring your CYA up or if you have a low level algae problem and need to sanitize.

 

[CJadamec]

Also adding the chlorine in the evening will keep your levels high over night and they will slowly diminish during the sunny part of the day. That's keeps your average FC level higher in the pool for the day.

 

[babsh]

Thanks everyone!