I had the pool acid washed due to likely scale forming, even though the CH got only to about 400. The tap is CH of 80. I'm going to be super careful this year with all my numbers, but want to also run the CH as absolutely low as is safe, to help prevent the scale. I've read everywhere that "150" is the lowest I can go. Is this correct? I've started using the pool calculator, and putting in trial numbers---I can go a bit lower than that, and still have a safe "csi." Can I ask what you would recommend?