Recommended CYA level

[hriehl1]

20,000 Gallon IG Vinyl
Greater Boston Mass climate
pool receives full sun dawn to dusk
I have Ben's PS233 kit and stay on top of PH and TA.

I have been practicing Borax and Baking Soda successfully for years, but used TriChlor 3" pucks in the skimmer for daily sanitizing and liquid 12% shock for shocking. While we never got nasty algae, it seemed there was always some showing on nooks and crannies of the steps and laddder. I think we under-sanitized, believing the OTO test that 1% or 1.5% was adequate when it wasn't.

This year we're going to try straight Bleach for daily sanitizing with a constant CYA that doesn't creep up as the season progresses (which we got from TriChlor).

My basic question is what CYA level would be recommended for a pool receiving full sun dawn-to-dusk in the moderate climate of greater Boston MA (daily high temps usually low-mid 80s)? I plan to add bleach each evening so it can do its thing overnight before the sun gets to it the following day... but what CYA level would afford decent protection through the day before that evening's next addition of more bleach?

I'm thinking 30% to 40% CYA, but the full-sun issue has given me pause that maybe I should run a bit higher, so I thought I'd ask others.

Once I have set my CYA, I'm fine with monitoring bleach dosage to keep above minimum CH levels for my chosen CYA level while still providing enough CH for daily sanitizing.

Thanks

 

[frustratedpoolmom]

If you target 50ppm CYA to start, backwashing your DE filter will cause it to drop slowly over the course of the season. You should be fine with a level of 50.

 

[cubbybeave08]

I get sun from 9 am to 6-6:30 pm...depending on what month it is. I have been keeping my CYA at 40 ppm. It seems to do just fine. Last year I targeted my FC to be at 3-5 ppm. This year I am following the pool calc guidelines and that should be 4 to 7 ppm. So I am adding about 30 to 50 ounces of 10 % bleach each night...This seems to work ok for me I have yet to have any kind of algae or other problems. You should be fine between 40 and 50 ppm. I would not go too much higher than that.