I've been re-reading Pool School now that we finally have the pool finished and filled. The chemistry is making much more sense now that I have moved out of the "conceptual" and into the "hands on" learning phase.
One thing still puzzles me. I have a SWG and see where the water balance section and some of the other guides on this site recommend a higher CYA level for SWG pools. Or more accurately, the chart recommends a more narrow CYA level for a salt pool.
I'm still trying to wrap my head around these 2 concepts:
1. Why is the range recommended in the Chlorine/CYA chart for SWG pools more narrow than for non-SWG?
2. Why is there a different recommended chlorine level by CYA in one vs. another? For instance, in a non-SWG pool, at 60/70/80 CYA respectively, the chart puts the recommended FC level at 7/8/9. However, for the same CYA level in a salt pool, the recommended FC level is 4/5/6.
I understand "what" I need to be targeting. I just don't get the "why". Can someone help me clarify?