The chlorine tabs, if they're the kind that you use in a feeder, are trichlor--a form of chlorine that also contains CYA. Depending on what you're using for "shock", it's probably dichlor, which also contains CYA. Continued useage of those is why your CYA level is so high. In addition, strips are notorious for not being very accurage, so you never really know for sure how much CYA you actually have.

What the strips don't tell you is that a CYA level of 100 is "ok" IF you run your pool with a FC level of 8-15 ppm and shock up to at least 25 ppm. If you let your chlorine get below 8 ppm, you're asking for algae blooms and unsanitary water. Take a look at the "best guess table" stickied at the top of this forum--you'll see that as your CYA (stabilizer) level increases, so must your base chlorine level in order to keep your water clean. So with your CYA as high as it is, I certainly wouldn't use anymore trichlor tabs or dichlor shock--I'd switch to bleach, which won't raise your stabilizer anymore.

I also would encourage you to get a test kit of your own that is drop-based, not test strips. A good kit is key to managing a clear, clean pool with very little effort. AT the very least, I would advise you to either take a sample to the pool store to be tested by the reagent method or even to go to WalMart and get the 5-way test kit (which includes a CYA test) and test it yourself.

Eitherway, you're either going to have to up your chlorine to compensate for the high CYA levels, or drain/refill part of your water to lower them, if you don't want to fight your pool all summer.

Janet