Quote Originally Posted by PoolDoc View Post
How do you know this? If you are using test strips, or trusting dealer testing . . . you do NOT know that this is so. There are some dealers with accurate testing, but they are the exception, not the rule. And 'guess-strips' are, well, 'guess strips'!

Read the test kit info page in my signature; buy an HTH 6-way drops kit from Walmart, if it happens to be available in your area.
Well, I know it's crystal clear since I can see that it is. I use a PentairPro II Test Lab to test the water and double check with the pool store now and then. Calcium hardness will always be on the high side here since the water is very hard. It's also hot and windy around here so I'm seeing a lot of evaporation during summer and have to refill with hard water