CYA levels: TFP vs Pool Store??

[Bart]

Backgound - I'm a new pool owner and the pool opened late last fall and then closed before any activity happened. The pool company came out this spring and added salt for the first time, but didn't add any stabilizer. From reading TFP I learned that you need to add CYA to stabilize the cholorine.

Advice I got in TFP suggested I should add 25-30 lbs of stabilizer so I went to my local pool store and asked for 25 lbs of CYA. The guy in the store seemed shocked and thought that was way too much, so I ended up buying 2 6-pound containers of CYA. I slowly added all 12 pounds and waited a week or so and took my water to be tested. The results are below, and the pool guy thought they were perfect. But when I checked the SWG page at TFP, it suggested the CYA should be 70-80 ppm.

So who is right and why? My "perfect" levels are half of what's recommended here, (but I know that lots of things are recommended in here that the pool store guys don't agree with!!!).

Here's my results:

pH 7.4
Total Chlorine 3 ppm
Free Chlorine 3 ppm
Alkalinity 125 ppm
CYA 40 ppm

I already know I'm probably going to need to double my CYA, but how do the other numbers look? Is the chlorine too high?

Thanks!
Bart

 

[woodyp]

Double the CYA and you're golden.

 

[JasonLion]

SWGs don't need to run as long when the CYA level is higher, so they last longer and you don't get as much PH drift as you would at lower CYA levels. SWGs also help prevent many of the problems that cause us to recommend lower CYA levels when you don't have a SWG, so you can be just as trouble free despite the higher CYA.

 

[Bart]

Thanks folks! So is the pool store guy just giving me the generic answer for a "pool", not a saltwater pool?

 

[JasonLion]

Yes.