How do you counter act upward pH drive from aeration?

[joecooler]

Per title, I've got the balance of my water pretty well dialed in, TA is at 70, I can get the pH down into the mid-7's by adding acid, but once I use it and run the jets, back up it goes to 8-8.2 Is there anything I can do about this? Do I need to? Do I just keep adding acid until it stays in the 7's? Or will it drift back down on it's own if I don't use it for a bit? I am currently using it daily so it seems like it doesn't have enough time to go back down.

Thanks,

Joe

 

[Arobbert]

I've found I need an AK of 50 to get a stable PH. This appears to be the norm.

 

[jowenece]

I would suggest reading the TA section here: How do I use Chlorine in my Spa (or pool)?

Right after a refill I add enough acid to bring the ph down to 7.2 and then aerate it back up to 7.8 or higher by running the all of the pumps with the air jets on. Keep doing this until eventually the ph only comes back to 7.5~7.6. If it doesn't rise far enough you probably overshot it a little. Usually takes me 4-5 hours. A TA ~50 ppm seems to be the magic number where my ph stops rising.

Also, I used to try to keep my TA a little higher > 80ppm to keep my -.3 < CSI < .3, but then read a post that with acrylic it's fine to have a -0.6 < CSI < 0.3. With my TA ~ 50 my CSI is around -0.4 and I've not experienced any problems. PH also stays stable longer now. So if you have an acrylic tub this might be a helpful tip. Maybe others can clarify as well.

 

[duraleigh]

All good advice.

Reducing your pH with muriatic and then raising it back with aeration permanently lowers TA.

That's normally a good thing but you want to be mindful that you could inadvertently lower TA below 50 which is probably not a good thing as your pH might become very unstable

 

[santacruzpool]

In my tub the PH settled in when the TA was just under 50 and it sits right around 40.

 

[joecooler]

Yeah I've read that post about chlorine a million times but I always come away with more questions. :-D Wasn't sure if the pH would stabilize eventually as I add acid. Kind of kicking myself here as my starting point after the refill was a TA of 30 and a pH around 7.8. Probably should have just left it alone but instead I upped the TA ... which of course increased the pH. Doh!

I will follow your advice to get the pH down again, and check TA while I do it so TA doesn't get too low. If TA gets below 50 and pH is still high, should I just call it good? I feel like my pH isn't awful right now, just not perfect.

 

[duraleigh]

but instead I upped the TA ... which of course increased the pH. Doh!

If you use baking soda to increase TA, it will have very little affect on the pH.

I post this all the time....it's a good reminder how to manage these two sometimes confusing parameters.

Lower pH - use muriatic....TA also comes down
Raise pH - use borax.....it has little effect on TA.
Lower TA - acid and aeration method....see Pool School
Raise TA - use baking soda....it has little affect on pH

 

[joecooler]

Yeah I have all these chems I got w/the spa (new as of last November) that I have been using, because they were free and I don't want to just throw them in the trash. But maybe its time to make the switch to the TFP methods.

 

[duraleigh]

because they were free and I don't want to just throw them in the trash.

Reminiscent of the Homer Simpson episode where he kept getting sick from the rotten food in the 'fridge but he was relieved in that there was just one or two meals left. Toss 'em out!

 

[joecooler]

Ahh Homey ... my hero!

 

[dunginhawk]

This to me is the KEY to TFP hot tub... get to the point where all you are doing is adding chlorine, or using SWG... chacking CYA once in a while... other than that it should sustain itself.

 

[joecooler]

That is the dream ... right now I feel like I'm close, the SWG is doing great keeping the chlorine levels up; if I can get my pH down I should be on easy street right?!