Looking for a little advice on my pH

[Salpal]

Hello.

Ever since I started using the TFP methods for balancing my pool, my one hang-up has always been the pH. Everytime I test, I feel like I sit there and stare at all of the pretty colors until my brain forces me to settle on one. I use my best judgement but I never walk away feeling confident.

I opened a few weeks ago and my pH sat at 7.2 so I didn't touch it. However, yesterday, it looked like a 7.0 to me so I bought some 20 mule team borax, used Pool Math to figure out how much I needed to get to 7.6, and added it. Ran the pump for 2 hours after.

Now, I think I'm reading an 8.0... Literally going from too low to too high in a matter of hours. But, as I said earlier, I'm not confident in these numbers.

I tried putting one drop of acid demand in the tube and that made it look like a 7.6 to me.

My tests are mostly done outside although the weather around here lately has been weird so I can't guarantee that my lighting is consistent. I do put a paper plate behind the tube. My latest test that read 8.0 was done indoors under incandescent lighting because it was dark outside.

I don't really have questions but am looking for some guidance on this. Are there any tricks to reading this test better?
I did take a photo of the most recent test though I doubt the accuracy of that. Here it is, anyways.

My other numbers:
FC: 8
TA: 80
CYA: 40

Any nudges in the right direction are appreciated. Thank you.

 

[Texas Splash]

My eyes don't like a white background. I do better with beige myself, up against my house siding. I take my glasses off which seems to help my old eyes. I think you'll find several personal methods here as the replies come in as to how owners feel they get the best reading, As for the jump in pH after the dosage, make sure to keep track of other chemical "projections". Perhaps your pool size isn't quite the size you think it is which is causing more change that you planned for? We've seen that happen many times.

 

[kellyfair]

I hold it up to my kitchen window... the color usually matches one of the blocks perfectly.

I do recommend undershooting Pool Math just a bit. Can always add more if needed, easier to do that than to correct an overdose!

 

[funandsun]

I hold it up to my kitchen window... the color usually matches one of the blocks perfectly.

I do recommend undershooting Pool Math just a bit. Can always add more if needed, easier to do that than to correct an overdose!

I struggled with it too and sometimes I settle on an in between like 7.5.

As for me, I hold mine up facing out a window to the sky. That works for me and seems to keep everything in harmony over here.

I am sure someone out there probably stands on their head lol

I mostly just target .2 increases and retest. I have done what you did, went for .4 and got .8 out of the deal. ugh.

 

[Salpal]

Thanks, everyone.

I tinkered some more and find that the beige background of my deck was a better background. Everything looked uniform and my eyes were able to really hone in. I think I was just on the edge of 7.8..... Probably a 7.9.

I bought some acid, undershot the pool math recommendation a little bit, and now I'm sitting at a very clear 7.4.

 

[funandsun]

Thanks, everyone.

I tinkered some more and find that the beige background of my deck was a better background. Everything looked uniform and my eyes were able to really hone in. I think I was just on the edge of 7.8..... Probably a 7.9.

I bought some acid, undershot the pool math recommendation a little bit, and now I'm sitting at a very clear 7.4.

Well done!!

 

[Oly]

For me it's a red vs yellow comparison, meaning if I see only red it is 7.8 or above and requires treatment. If I see yellow (never) then it's acidic. Hints of orange is what I am looking for using only slight 0.2 or 0.3 corrections based on Pool Math and experience. Don't go overboard and watch your CSI in Pool Match for direction.