First of all I want to thank everyone that answers these posts.It is appreaciated.Now for my problem.Have opened my pool 21 foot 9500 gallons.Testing is giving me the blues.I can not get a reading for the chlorine test.I have put 2 gallons of bleach in so far and 1 floating 3 inch chlorine puck.The water seems like it is turning a faint green color.Will that get my reading up so I can get a reading to start with?Have followed some of the post and have got the PH TO 7.6(concentrating on PH was preached a time or two).It was reading awful low 6.8-7.0 last night.Put a half box of BORAX in.That's the chemical problem right now.Now for the bleach calculator, how do you get a BORAX reading off of it?I am learning as I go with clorine.I was duped into using Baq for a time(5 years). I drained the pool when I closed it last fall and scrubbed and sanitized tank .Now comes the learning curve with chlorine.