On Sun, 06 Sep 2015 12:51:21 -0500, CRNG
wrote:

We put in a small spa last month and I'm wondering why the pH tends to
drop over time. I'm guessing that all the air that is pumped through
the water when the air jets are on somehow causes the water to
become acidic (via the CO2 present in the air). Is that a reasonable
guess?

Keeping a small spa chemically balanced can be a task. (What do you
use for a sanitizer? Chlorine or Bromine)

Some tips he

http://www.spa-daddy.com/ph_total_alkalinity.php

http://www.spadepot.com/shop/Chlorine-W18.aspx

http://www.spadepot.com/spacyclopedia/spafaqwc.htm

http://www.frogspawater.com/p/spa-care-systems.html