A bit of CYA confusion

[Skiddy]

So I have a decent grasp on my new pool equipment and the chemical balance has been pretty easy since I picked up the Test kit from this site. I had my first vacation return home stint with algae and was able to do a mini slam and get it back to normal without too much trouble and just chlorine. I have recently noticed I am getting different target ranges for CYA and I really dont know where my actual range should be. The pool math app seems to think im too low sitting at high 30's low 40's and I should be up around 70+ but my test kit tells me I am perfect where I am?
Can someone expound upon this as to why Im getting two different recommended target ranges?
Thanks

 

[mknauss]

You have a SWCG.
Follow Recommended Levels

 

[Skiddy]

yessir

 

[Skiddy]

Is there a reason why the CYA is to be higher with a SWG?

 

[mknauss]

A SWCG slowly adds chlorine to the pool. It was found through testing that an elevated CYA allows for less chlorine creation per day by the SWCG, or in other words, a lower FC loss per day.

It is up to you. If you are happy with the FC stability of your pool with your current CYA level, and your SWCG can keep up with the FC loss each day, then leave things be. I would not go below 4-5 ppm FC in your pool water, regardless of your lower CYA.

I also would suggest you test FC every few hours during a sunny day that should be consuming the most FC. I know your pool is in a screened enclosure which does reduce the UV impact on your pool surface.

 

[Skiddy]

Thank You for the explanation. It is hard to get any consistent results right now due to the afternoon rain patterns we are in here in FLA. I had to add more salt recently due to draining my pool 2-3 x per week this month. If I can get a few days without rain in a row I will do some testing.