I want to add some calcium to my pool. What is the percentage of calcium chloride to use. Some pool products say active ingredient 100%, others say on average 97%. I am sure 100% is ideal, but i have some ice melt which says 94% pure calcium chloride. My only concern is what the other 6% is. The Pool math app doesn't mention the percent of calcium chloride, just how much to use to raise ppm. Any input would be appreciated. Thanks