Recent Test

[Michaelg90]

So I have been using the the Tf-100 for a little over three weeks now and love it. I recently have been testing my pool water (doing full round of tests every Saturday with PH/Chlorine daily) and noticed my Alkalinity was an 80 this Saturday and my P/H was 7.4. I wanted to lower my PH to 7.2 as I’m trying to get my plaster surface for the first year on the lower end to make sure everything cures nicely and slowly remove any first year scale or rookie mistakes I make. I placed the pool math recommend amount and rechecked the PH and it was perfect at 7.2. Checked on Sunday and it was back to 7.4. Did the acid agian. Checked today back to 7.4. I checked my alkalinity as we had some rain last night which seemed odd that the PH increased since that should have helped me reach my ph goal and it came in at 70. So it dropped 10ppm.

How can I get the PH to stay at 7.2? Should I increase my TA to 100? I do have two fountains (pictures attached) and was curious if that has a major affect due to the aeration? I also have a built in drain/refill so it does remove and add water automatically when necessary however in this case it would have drained excess water (which would have been acidic) so my PH shouldn’t have moved.

Thank you

 

[Texas Splash]

If I understand you correctly, you're wanting to lower the pH in an effort to help what you call, "as I’m trying to get my plaster surface for the first year on the lower end to make sure everything cures nicely and slowly remove any first year scale or rookie mistakes I make." correct? So is this your first year with the new pool/surface? Can you confirm when it was installed/plastered?

It's important to be careful about driving the pH down low for extended periods. Those in areas with very hard water (i.e. southwest) may have to do that to compensate for a very high CH, but you shouldn't. It would help to see all your test results as other factors (including water temp) will tell us if a pH of 7.2 is advisable.

Yes, aeration can certainly increase pH, and so can an elevated TA. But again, Before we get too far ahead of ourselves, please post a full set of numbers and confirm the age of your plaster and we'll go from there.

 

[Michaelg90]

Age of plaster is 4 months old. Complete test from Saturday

FC : 7
CC: 0
TA: 80
PH: 7.4
CYA: 60
CH: 350

Temp: 80 this weekend been 75 or 73 mostly for the past month.

 

[Texas Splash]

It's good to know you're past the 30-day mark on that new plaster. So a lower pH and CSI isn't a huge problem. When I plug your numbers into PoolMath, using both pHs of 7.2 and possible 7.6, your CSI (plaster health) is good either way. The 7.2 is actually a hair too low (-.34), so if the pH creeps-up to 7.4 again, I would leave it there. That makes your CSI a -0.15 and that's a good place to hang for a while.

 

[Michaelg90]

Okay sounds good. I appreciate the advice. So with TA on the lower end of the 70 to 90 scale I’m good as well I take it?

 

[Michaelg90]

The new TA came in at 70 when it was 80 on Saturday

 

[Texas Splash]

So with TA on the lower end of the 70 to 90 scale I’m good as well I take it?

Absolutely. It's working with your pH, CH, and water temp to be in a healthy CSI range for your plaster to avoid scale or erosion. As the season goes on, if any levels change drastically, let us know and we can go from there.

 

[Texas Splash]

The new TA came in at 70 when it was 80 on Saturday

I see. Yeah, the lower TA lets the CSI drop even a little lower to -0.41. So I would simply let the pH rise a bit to 7.4-7.5. You'll be in a good place there.

 

[Michaelg90]

I see. Yeah, the lower TA lets the CSI drop even a little lower to -0.41. So I would simply let the pH rise a bit to 7.4-7.5. You'll be in a good place there.

The pool builder recommended I raise the TA up to 100 and keep it there ongoing and try to keep the PH on the lower end 7.2 to 7.4 to avoid scale or pool issues. With CYA at its current level and chlorine being maintained as needed, the CSI looks even better at those levels. Would this not be the recommend course of action?

 

[Texas Splash]

The pool builder recommended I raise the TA up to 100 and keep it there ongoing and try to keep the PH on the lower end 7.2 to 7.4 to avoid scale or pool issues.

What that means is "trying" to maintain a higher TA w/ a lower pH, or the other way around. In reality, we all hope to find a pH/TA "balance". That perfect "Zen" world where the pH and TA stabilize at the perfect CSI level. Trying to "make" your pH stay low is sometimes impossible, and eventually you drive the TA too low causing a yo-yo effect. While the builder's advice to keep the pH low seems right on the surface, it doesn't take into account your overall CSI (see PoolMath) and what it will do to the TA with each acid dose. Using PoolMath, which accounts for water temp, TA, CH, and pH, your pH is a bit low which over time has the potential for corrosion/etching. So letting the pH ride naturally back to about 7.4-7.5 resolves that. Your TA may also remain steady at 70-80 which would be good as well. Always enter all your test results in the PoolMath tool or app to see what your overall "CSI" is if you are overly concerned about scale. But in general for your area, I would think that as long as you stay within all the TFP Recommended Levels (link below), you'll be fine.