I lowered my water line by an inch and now I see a new scale line.
I have recently been enlightened, having learned about TFP, water balance, CSI, etc. Before my enlightenment, I had allowed a stark ring of scale to form. Most likely by allowing my CSI to drift too high in the positive range. At the beginning of the summer I removed this scale with elbow grease by chipping and scrubbing with pumice stones.
I am now a little discouraged because the scale is beginning to return. I have tested my water almost daily throughout the summer and have kept my CSI in the negative range -0.1 to -0.3.
The CSI is an overall indicator of corrosive versus scale-prone water. Water with a CSI level that is slightly negative should remove just a tiny bit of scale - not deposit it.
CH 550 (fill water 110)
Salt 3800-4500 (depending on who does the test)
LSI 0.13 (from the Taylor Watergram wheel)
My CH is high so I have to be careful to keep the CSI out of the positive range. However, the corresponding LSI is slightly positive. I hate to say this but does this mean that the LSI is more accurate? If it were more accurate it would explain the deposit of the scale. Am I correct in assuming that slightly corrosive water should not deposit scale?
I may need to do a partial drain to get the CH down so that I don't have to fight the scale as hard.