If you don’t, the minerals will start dissolving after install. If the pump is not running, the minerals will dissolve in a concentration at the bottom of the basket, and when the pump turns on several hours later, 20,000 gallons of concentrated minerals blow through the system and into the pool, in a big plume of undissolved minerals. If this happens the minerals don’t have time to dissolve properly into solution and they can stay in granular form and stick the scale on the surface turning it a blue-ish color. There is a simple fix, we recommend Jacks Magic Blue stuff. It’s a phosphonic acid that will help dissolve the mineral off the surface and into solution. See FAQ 24: I made a mistake. How do I fix it?