Quote Originally Posted by fofa View Post
Something we learned the hard way. We had our pool renovated 5 years ago. We had limestone used instead of tile/coping. We have been having ongoing problems with the limestone flaking, cracking, etc.
One day talking with a stone dealer (for something else, they did not supply stone for pools) I found out there are different "grades" of limestone. The cheaper grades act as the limestone in our pool (which I have been using tri-chlor pucks, bleach only so far).
Anyway, I am no expert but just thought I would pass that on.
So this would indicate that the quality of limestone is a primary factor since your pool is not a salt pool (no SWG). Technically, even non-SWG pools have salt in them, of course, but generally it starts at around 350 ppm (the sodium from the bicarbonate and the chloride from the calcium chloride, plus some more chloride from muriatic acid) but usually stays below 1000 ppm with regular dilution from backwashing.

Just to be sure, do you have a DE or sand filter that you regularly backwash or do you have a cartridge filter and yet manually drain and fill part of your pool water? I'm just trying to get a handle on the salt levels in your pool.

Richard