Low Calcium Hardness. When pool water becomes too soft (i.e. its calcium hardness drops below 150 ppm) it becomes corrosive. Nov 20, 2017 - Good calcium hardness levels make managing pool chemistry so much . California, and our weather is pretty awesome, most of the year. Conversely, there is no simple chemical addition that can be made that will reduce calcium hardness. The only way to reduce calcium hardness levels in pool . May 18, 2017 - Hey All. SLAM is DONE.pool looks AMAZING!!!A million thank you's.So all levels are good, except calcium hardness came in at 230.2 . Jun 5, 2018 - Dealing with calcium hardness (total hardness) in a vinyl pool? Well stop right now! Calcium hardness is one balance step you don't have to . hth® calcium hardness increaser is used to raise the calcium hardness of swimming pool water. . My pool looks amazing and didn't take much effort! The Hth pool calcium hardness increaser is compatible with salt based systems, as well as fresh water. My pool looks amazing and didn't take much effort! Incredible water quality and swimmer experience! Don't be . Total Alkalinity, and Calcium Hardness) to keep swimming pool water clean, clear and trouble free. Apr 18, 2010 - Don't worry about the calcium hardness level for your vinyl pool. . you an AMAZING song-and-dance about why you need calcium in your vinyl . pool. High pool water calcium hardness levels, especially above 400 PPM, can sometimes reduce the clarity of water and cause scaling issues. Use Cal-Stop™ .