Lowering TA (alkalinity) by aerating a connected hot tub

[mmann3200]

The water in our hot tub circulates with the main pool via spill over. It also contains 1 of the 5 total returns (4 in the pool). The question is, will turning on the 4 jets in the hot tub achieve the aeration I need to lower my total TA? pH is currently 7.2 (down from 7.8). I aerated in this manner for about 4 hours, but suspect this wasn't nearly enough as I didn't' notice a rise in pH. Has anyone ever been successful with this method? Maybe I'll run overnight to see...any feedback would be greatly appreciated!

[BigDave]

I think that's a great way to aerate. Do the hot tub jets also add air? That would help. Also point the jets at the surface and let it spill over the entire time. Don't forget, POPP (Pool Owner Patience and Persistence) is essential to the alkalinty reduction process.

[mmann3200]

Quick update: Ran hot tub jets overnight and after 12 hours, no change in pH or TA. Both measured values remain ... pH = 7.2, TA = 130. I know I'm being impatient thinking (hoping) TA will drop / pH will rise faster so I left filters and jets on today. Detail of pool and chemistry below:

Size:In ground concrete, ca. 30,000 gallons

[PoolDoc]

Lower your pH to 6.8, and then aerate. Your TA (Alk) is already fairly low, so aeration is not going to produce rapid reduction.

Please also note that if your spa is not MIXING the water with your pool, aerating the spa will have no effect on pool water. Many pool/spa combos are plumbed to share equipment, but not to actually share water. Some like yours may be combined OR may simply mix on an occasional basis.

If your spa's spillover runs CONTINUOUSLY into the pool, you have shared water. And, the spillover itself should provide all the aeration needed.

Quick sanity check? If you can maintain your spa water at a different temperature than your pool, aerating your spa will likely have LITTLE or NO effect on your pool water.