I had a 19,000 gallon inground pool put in last summer. The equipment setup has a Zodiac Nature2 Fusion inline chlorinating system that takes 3" tabs. It also has the mineral cartridge.
I've had zero problems with it until about a week ago, when the chlorine reading was at 1 or so (just a faint hint of yellow in the test kit) even though I had 6 tabs in it. I brought a water sample in to two different pool stores, and they both said the CYA was at 200.
I've combed through a lot of the information on TFP since then, and it's no surprise that the CYA is high because all I've done for a year to chlorinate is run trichlor tabs.
Which brings me to the question, what use is the inline chlorinator if it will eventually drive up the CYA levels to where they become a problem?
As an aside, I haven't replaced the cartridge yet, and am getting the feeling that it might not be needed. Thoughts?