I have our local reverse-osmosis provider scheduled for later this month. My goal with the process is to get the CH number down from it's current ~725 number to somewhere in the 250-300 range. With that plus adding borates I hope that I can allow the pH to stabilize in the 7.8-8.0 range and still have the CSI remain in the acceptable -0.3 to +0.3 range. That in turn will hopefully reduce the frequency of acid additions from the current pace of every 3-4 days. (I have 15 lbs of boric acid from Duda Diesel sitting in the shed ready to go.)
My working assumption is that in reducing CH, the TA, CYA, Salt numbers will also come down proportionately. I am also assuming that pH should not be particularly effected by the process or perhaps drop a bit. So mapping that out:
Assuming this is true, do I need to be concerned about raising the TA before proceeding with adding the boric acid?
My inclination is "no", but to add back the needed CYA (which will raise the TA a bit), get the salt level back to where my SWG is happy (probably 2800) and proceed with adding the boric acid. And the once that it settled add baking soda if necessary to raise TA to get the CSI above -0.3.
The RO folks say that "re-balancing the water is part of the service", but I plan to just waive that off unless the pH does drop too low , in which case I will ask them to add either Sodium Carbonate or Borax to raise it back to ~7.5.
Aside to @JoyfulNoise I did try bringing up the CYA to 60 over the summer, but I can't say that made a major difference in the amount time needed on the SWG. It appeared to be pretty much the same except for a short period where the demand rose which corresponded to the hot spell where the pool was ~90F.
My working assumption is that in reducing CH, the TA, CYA, Salt numbers will also come down proportionately. I am also assuming that pH should not be particularly effected by the process or perhaps drop a bit. So mapping that out:
CH | TA | CYA | Borate | Salt | Temp | pH | CSI | |
Pre RO | 725 | 80 | 40 | 0 | 3200 | 85 | 7.5 | 0.125 |
Post RO | 300 | 33 | 17 | 0 | 1324 | 85 | 7.5 | -0.514 |
After all adjustments | 300 | 80 | 40 | 50 | 2800 | 85 | 7.8 | -0.014 |
Assuming this is true, do I need to be concerned about raising the TA before proceeding with adding the boric acid?
My inclination is "no", but to add back the needed CYA (which will raise the TA a bit), get the salt level back to where my SWG is happy (probably 2800) and proceed with adding the boric acid. And the once that it settled add baking soda if necessary to raise TA to get the CSI above -0.3.
The RO folks say that "re-balancing the water is part of the service", but I plan to just waive that off unless the pH does drop too low , in which case I will ask them to add either Sodium Carbonate or Borax to raise it back to ~7.5.
Aside to @JoyfulNoise I did try bringing up the CYA to 60 over the summer, but I can't say that made a major difference in the amount time needed on the SWG. It appeared to be pretty much the same except for a short period where the demand rose which corresponded to the hot spell where the pool was ~90F.