Balancing chemistry on indoor pool

  • Last Post 28 November 2018
HappyGrandma posted this 28 November 2018

We had installed in May this year an 18,000 gallon 16x32 gunite pool with saltwater generator and gas heater.  It is 18" above the ground and totally screened in with a metal roof.  It gets almost no direct sunlight, very little debris, and no rainwater.  The pH has never been balanced and seems to stay in the mid 8 range. We add muriatic acid every week.  We had  to turn off the SWG because the chlorine levels were always above 4 ppm, sometimes 6ppm.  The free chlorine is now 3.03ppm, but the pH is 8.5.  The ONLY time we got the pH down (7.6), the alkalinity went to 0.  Brought the alkalinity back up with sodium bicarbonate (94pppm) but the pH is back up to 8.5.  The hardness is now 395ppm which is high.  We get conflicting advice depending on the rep you talk to.  One said use pH minus, one said never use that in a saltwater pool because of the sulfur.  One said don't add Cyanuric acid because there is no UV exposure, one said keep that level at 30ppm.  Help!

HappyGrandma posted this 28 November 2018

Our current chemistry is:

Free Cl   3.03ppm                                             Hardness   395ppm

total Cl   3.21ppm                                             Alkalinity    94ppm

Combined Cl  0.18ppm                                    Cyanuric Acid    10ppm

pH  8.5                                                             Salt    3400ppm