New Water/Refill

[chem geek]

cool, my next question is the Hardness ....that calc chloride stuff is $$$$$ is there an alternate store bought product? I'm @ 40ppm ....need to get up in the 200 range I suppose...

You could use Calcium Hypochlorite, also called Cal-Hypo, which will increase both your chlorine (FC) and your calcium (CH) levels. Try and get the 65% purity form of Cal-Hypo unless it's much more economical to get a less pure form. One pound of the 65% stuff in 10,000 gallons will raise the FC by 7.7 and the CH by 5.5 so if you switch to using this instead of liquid chlorine or bleach as your chlorine source, then you can slowly get your CH level to increase.

Also, your combination of pH, Alk, and low CH have your pool water in a corrosive state and though normally we don't talk about that because the number has to be pretty extreme to cause a problem, your numbers lead to an index of -0.76 which is where I might start to worry (we don't have good data from forum users when corrosion occurs, but on the other side with scaling and cloudiness some report this at an index of +0.75 while others report it only when they get to +1.0). Though it is true that the curing of concrete will lead to an increase in pH and alkalinity, it is also true that corrosion (dissolving) of your concrete will also have these same effects. If I were you, until you get your CH level up I would keep your pH much higher, perhaps at 7.8 or so. As you add more Calcium you can then lower your pH level. Perhaps I'm being over-conservative in this but adjusting the pH is a pretty easy thing to do compared to the other items.

One final note: though the Calcium Chloride is not inexpensive, it's only something you will do (in large quantity) once. It's not an ongoing maintenance item unless you have large amounts of backwash or splash-out.

Richard