I am preparing to install a saltwater lx pool and have prepared the site with crushed limestone (we don't have sand around here, we call it ag lime). I know that high pH protects metal up to pH 11 or so. I would like to bury the pool 27 inches and the manufacturer recommends using sand or rock free dirt. Do you think that it would be ok to back fill with the lime or would that increase the pH too high over time? I can probably filter enough dirt to contact the pool...over time. Thanks for your opinions.