CYA Through the roof?

[polyvue]

Thank you for responding so quickly. Since I don't really know how high the CYA is, should I only drain it half way and check it after refilling? What I don't want to do is find out it is still too high and have to drain partially and refill again. Any idea how it could have gotten so high or could anything else cause this result to be incorrect?

Watermom has deciphered the most likely cause. You can always repeat the CYA test but if you've been using TriChlor or DiChlor tablets or shock powder, this is the culprit. CYA can build up very quickly (a matter of a few months) when using chlorine compounds such as Trichlor. You can also try diluting the pool water sample with tap water (50:50) on your second test and double the result. Either way, reducing the CYA by draining some pool water will make it much easier to manage the pool chemistry.

I notice also that you didn't state the Calcium Hardness (CH) level. If your pool shell is composed of concrete/plaster or tile you might want to consider changing your chlorine source to Cal-Hypo -- but you must monitor CH level so the calcium doesn't get too high (> 400 ppm). My pool setup uses a Salt Water Chlorine Generator (SWG) cell to santitize but if I didn't have one I would use straight 6% bleach or 12% liquid chlorine. No additives and no worries about too much CYA or calcium.