How do you lower alkalinity but not change pH in a swimming pool?
Initially, you can’t. What you do to lower alkalinity is first lower the ph to under 7.2, but not lower than 6.9. Then you aerate the pool, by creating bubbles with your brush, or by running a water feature, if you have one. This will lower your alkalinity. Maintain this lower ph and aerating until you get your alkalinity where you want it. Then retest your ph. If it is now too low, you add Mule Team Borax, say a 1/4 a cup, and then retest. The borax will raise your ph without raising your alkalinity. See the poolforum.com for more help if needed.
