Previously got good scoop from Jason about using the Pool Calculator to get my CSI slightly negative in order to loosen calcium scale which is blue in spots from use of copper based algaecide. Plaster is 5 years old and in good shape up until I took over pool maintenance a year ago, and before TFP! My fill water is CH 250 and my last test showed CH 525 which is now up from previous readings of around 475. ( I am still struggling to get everything balanced but making slow progress..) I understand that pH, CYA, and TA are the parameters that I need to control in order to get slight negative CSI, yes? Then I can add a scale and stain sequestrant and brush like crazy to begin to tackle my issues? Test results from yesterday were:
FC - 6.5
CC - 0
pH - 7.4
This is the best CYA reading I have had yet and TA was previously 90...don't understand how it crept back up. When I put in the following goals in the Pool Calc. I got a -0.25 potential CSI. Is this considered "a little negative"....how negative is sufficient for me to begin this process without draining my pool or doing an RO treatment? I get a little intimidated by the warning of plaster corrosion when I go negative....
pH - 7.2
TA - 90
CYA - 55
Again, what I am going for here is what you previously referred to as a mild no drain acid wash. Because of our climate and my solar heat source, we can easily swim in to early October some seasons so I can't do the Jack's treatment or a full on acid wash now.
Thanks for your patience. I am still struggling putting all of these pieces together...