Today I finished putting in 50 ppm of borates into my 30,000 gallon pool: 23 boxes + 16 oz weight Borax and the appropriate amount of offsetting acid (about 5 gallons). Success! Water looks awesome!
I followed the instructions as posted in the 'sticky' here, and all went fine.
I turned the filter pump on high speed (8 hours per turnover) before starting.
I applied the chemicals in thirds, wanting to be sure to not make a mistake.
Liquid acid (MA, 31% HCL) was spread around the edge of the deep end with just the deep end drain line open (skimmer drains closed). I put this in first, requiring about 10 minutes to carefully put each third in (at 4 cups per each pouring). After each third, I brushed the deep end walls and floor. (BTW, this exercise, putting acid in, was a good reminder on how nasty and dangerous MA is. Safety glasses are a must.)
Immediately after brushing, I put in each third of Borax through a skimmer. For the part of the procedure for putting in the borax, I opened up just the skimmer drain I put the Borax into, and closed the deep end drain (and then returned to filter suction just via deep end drain).
I did all three 'thirds' over a 1.5 day period. One third yesterday morning, one third yesterday evening, and one third this morning. I ran the pump on high speed the whole time, suction from the deep end only.
I tested the water chemistry (using a Taylor K-2006 kit) a couple of hours after each third to make sure I hadn't made an error.
I followed up this afternoon to check everything over, with the following measurements (in-ground plaster pool, using tri-chlor erosion feeder):
ph = 7.5
TA = 110
FC = 4.5
CYA = 80
CH = 320
TDS = 1100 (measured at pool store, before putting in Borax)
90° water temp
I used Richard's spreadsheet as I enjoyed learning the detail. It also showed my Calcite Saturation Index (CSI) is right at zero at the moment. Perfect! (noting the +/- 0.1 pH measurement accuracy with the Taylor colorimeter.)
Cost of Borax at local Kroger store was $4.50 per box (23+ total), and the acid at Leslie's was $6.00 per gallon (about 5 total). Total expense was $108 + $30 = $138 before sales tax.
Last thing yet to do is to get the FC back to being a little higher. Because I live in a location (Dallas) where in the summer the water is exposed to long days of a lot of intense sunlight, I use a lot of chlorine. Thus, I go through a lot of tri-chlor tablets which over time raises my CYA considerably. While running the pump on high speed non-stop for the past 36 hours, I turned down the chlorinator. Now that I've got the pump back to it's low speed schedule, I'll slowly readjust the chlorinator to raise the FC level to be back in line with the CYA.
Hope this posting helps others have confidence that if one decides to add borates to a pool, following the instructions as noted in the sticky works great!