I've been an occasional reader/lurker here for a few years and we've had our pool for 12 years, but we only recently (as in yesterday!) shifted to the BBB method. Up until this year, we've been OK with the pool store approach to keeping things in balance but this year it seemed that chlorine became hard to manage. Knowing what a wealth of knowledge TFP is, I came here and read up (again) on pool chemistry, specifically CYA. Due to our long-term use of chlorine tablets/sticks, it seems we'd been accumulating CYA over the years and this year we had levels approaching 100ppm. After a couple cycles of dropping the water level and topping off, we're now down to a manageable 80ppm or so. Still high, but we'll get it down.
My question is about the Taylor CYA test. We've got the Taylor K-2005 test kit, which is similar to the K-2006. Unfortunately, I saw that recommendation AFTER we'd already shelled out $65 for the 2005. But the CYA test appears to be the same. In any event, I wonder about the variability of the test due to ambient light. It seems to me that how much solution is in the tube before the black dot disappears is highly dependent on whether you do the test outdoors in bright daylight or indoors with dimmer light.
Anyone else have doubts about their CYA tests using this method? Anyone know of any other methods to measure CYA?