Why is higher CYA recommended with SWG?

[chebyshev]

I'm in the process of converting my pool to salt to start this season and I'm wondering why such a high CYA level is recommended with a SWG?

 

[Jimrahbe]

C,

Because you are adding a little chlorine over a longer period of time, it is easier for the FC to stay in the right range.. And... it helps to keep the sun from burning off the FC too quickly, which allows you to run the cell at a lower output..

It is not a requirement... Try running with lower CYA if you want... just as long as you always keep the FC above the minimum. I personally use the "target" as my minimum so that I don't need to test quite so often..

Thanks,

Jim R.

 

[chebyshev]

Thanks for the info Jim!

 

[SBall]

For what it is worth, my CYA is at 50, my IC40 is running at 40% for 18-20 hours per day, water temp is 90, and it is not really keeping up. I had to pour in a gallon of bleach to bump it up quickly. I ordered a 4lb jug of CYA off Amazon, and going to shoot for CYA of 70 and see if that helps.

 

[mknauss]

my IC40 is running at 40% for 18-20 hours per day, water temp is 90, and it is not really keeping up

You do not show a pool volume but from your dimensions I am guessing about 17000 gallons. Based on your run time data, you are creating 3ppm FC per day. I would suggest bumping your SWCG to 50% so it created 3.7 ppm FC per day and see how that goes.

 

[LFrankow]

I used to start mine at cya = 50, then around the 3rd week in june I would panic thinking my swg was broken/not working. Now I head straight to cya = 70, no more troubles.

 

[SBall]

You do not show a pool volume but from your dimensions I am guessing about 17000 gallons. Based on your run time data, you are creating 3ppm FC per day. I would suggest bumping your SWCG to 50% so it created 3.7 ppm FC per day and see how that goes.

Yeah, my guesstimate is right around 16k-17k gallons. One of my annoyances with the IC40 is the limited choices in output...I can either do 2,4,6,8,10% or 20,40,60,80,100%. From what I can tell, no way to do something else, like 50%, so I have been trying to adjust my run time accordingly.

 

[mknauss]

Without automation that is a limitation. You are on the right track.