First time posting, so here goes. I did do some research and found a lot of great info (Thanks!), but not an answer to my specific questions/issues.
My pool has had high acid demand (up to 2 gallons per week) and scaling issues since it was new. Adding that much acid would crush my alkalinity, so it was a constant battle between low alkalinity and high pH. Originally I followed the Taylor kit recommendations for chemical levels, then was introduced to TFP in October. I have been using the TFP guidelines since roughly November, and my acid demand has gone down dramatically (but then so has my water temp). My pool builder gave me a sample dosage of a Natural Chemistry product called Foundation, which boosted my borates to 15 ppm. I would like to increase it to the TFP recommended 30-50ppm, but just haven't gotten around to it.
Here are my test results from Saturday 2-7-2015 (Taylor K-2005 + TFP FAS/DPD):
Water Temp: 62F
When I plug these numbers into Pool Math, I get a CSI = -0.7. I have checked all of my chemical tests going back to December, and I am always on the negative side of the CSI scale, and yet I still see scale developing. Now I do have a black bottom pool, so it is definitely more visible. I just don't know why this keeps happening when I am close to being corrosive on the CSI scale.
I have drained and acid washed the pool once. My spa has been done twice, and I am told it can't be done again. My builder is suggesting we try the Jack's Magic before draining again.
What am I missing? Thanks in advance!