Tap water has no CYA in it.

Which Taylor kit do you have, the K2005 or the K2006?

You need to get some chlorine in there ASAP! Since your chlorine has dropped down to 0 and your pool is cloudy, you need to shock your pool. Shock levels and needed maintenance chlorine levels are dependent on your CYA reading. With a CYA of 80, you need to shock the pool up to 20ppm. Your CYA is already kinda high at 80 so you don't want to use anymore stabilized forms of chlorine such as dichlor powder or triclor pucks. Take your chlorine up to around 20ppm and keep your pump running 24/7 while you are working to clear the pool.

Keep your chlorine high until you meet three criteria:
1. You lose no more than 1ppm of chlorine from sundown one evening to within one hour of sunrise the next morning. AND
2. You have no greater than 0.5ppm of CC AND
3. Your water is clear.

Add a little Borax and bump your pH up some. It's getting kind of low. You never want it to drop below 7.0.

By the way, read the chart at this link. It explains the relationship between CYA and chlorine. http://pool9.net/cl-cya/

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