Ideal CYA level for me?

[kickinthethroat]

Hey all, I've been doing BBB method so far this summer, and its going great so far.

My CYA is finally getting low enough, to where I need to start thinking about what level I want to keep it at. Its at about 60.

Now, the guide says 'extremely high levels of direct sunlight' require 60-80... what is the definition of extremely high levels of sunlight?

My pool is above ground, 22000 gallons, no trees around it, so it gets sun most of the day. There is a deck on 1 side, so that kind of blocks direct sun late in the evening, but that's about it. At a CYA level of 60ish, I seem to be going through about 3.6ish PPM of FC a day (it went from 24.5 FC to 10 FC in 4 days, just got back from vacation ). Is that too much? What is an ideal level of FC loss in a day?

Thanks!

 

[jblizzle]

The ppm loss does not work as you described. You loose a % of the FC to the sun and the CYA level determines that % ... so 14.5/4 is not the right way to look at it.

It would be more like 24.5*0.8*0.8*0.8*0.8 = 10ppm making the loss around 20% every day.

There is nothing wrong with 60ppm for CYA. The higher levels will just protect more of the FC from the sun and slow the loss. The concern is if you have to SLAM and the higher CYA levels require much higher FC levels.

Just maintain the FC above 5ppm at all times based on the Pool School chart(pool-school/chlorine_cya_chart_shock) and you will be fine.

Most pools only lose 2-3ppm each day. If you start at 7ppm and lose 20%, that would put you about 5.5ppm the next day when you would raise it again back up to 7ppm ... or aim for 7.5 / 8ppm for a little more buffer.

 

[kickinthethroat]

Thanks for the reply! I'll think about it as a % now, thanks

 

[BoDarville]

kickinthethroat:

The definition of 'extremely high levels of direct sunlight' also depends on where you live. Full sun in AZ or FL is much more intense than full sun in ME or WA. Can you add your general location to your profile? Here's how to do it: What we need to know to answer your questions.

 

[kickinthethroat]

Done, I'm in Illinois

 

[Speedo]

Be sure you're doing the CYA test properly. If keeping FC higher than necessary the excess will be used up quicker. This has been my experience, I'm at about 45ppm CYA currently. Most often the highest consumption is about 3.5ppm/day when there's full sun and plenty of usage.

My reference thread has CYA testing details

 

[joepaiii]

kickinthethroat:

The definition of 'extremely high levels of direct sunlight' also depends on where you live. Full sun in AZ or FL is much more intense than full sun in ME or WA. Can you add your general location to your profile? Here's how to do it: What we need to know to answer your questions.

I know this is an old message but it addresses my question as well. What about Dallas TX? Should I shoot for a higher CYA like 60-70?

 

[jblizzle]

If you are losing more FC daily than you like, assuming the pool is clean and clear, then you can try raising the CYA. Just realize the SLAM is more difficult if required.