With a vinyl liner we normally do not speak of CSI - Calcium Saturation Index (CSI) - Trouble Free Pool. But, one way to slowly remove calcium is to keep your CSI below -0.6. Will not harm anything as you have a vinyl liner, but it will slowly dissolve the calcium back into the pool water. You need to enter your test data from a proper test kit into Poolmath to calculate CSI. Water temperature is also needed.