Quote Originally Posted by vinouspleasure View Post
thanks for all the great info! its a gunite pool, so I definitely need cal. also, my cya is 40 not 45...the actual reading was 38 but I rounded it off.

thanks again,
jd
It's not possible to get a CYA reading of 38 with the PS234. Just call it a bit below 40. Your CYA is fine where it is. Shocking to 15 ppm is still fine.
As far as refills, if your DPD powder is only grey it's probably still good. The titrant is the one to worry about. If it is NOT clear but has any kind of color (like pinkish or orange) then it is bad and needs to be replaced. You can order refills from Taylor Technologies or from TF Test Kits.