pH test

[tessv]

Hi all!!! I got some unexpected pH readings last night with the Taylor kit, so this morning I pulled out my pH stick and pH standard... wanted to show you the pic of my results using the standard 7.2 solution with Taylor...



Why would it be reading so high??? New kit rec’d in April, I believe... standard rec’d last week...

Relevance is that I’m working on bringing TA down, and was shooting for 7.2... my stick after calibration reads the pool at 6.9... while drops continue to hover in the 7.5 range...

Thoughts???

 

[justinc]

What was your free chlorine reading at the time you checked pH? Over 10?

 

[Donldson]

Three questions come to mind to verify before considering that either the standard solution or phenol red are bad:

Have you tried taking it out in the sun and holding a white sheet of paper behind it just to confirm it's reading 7.5 on the standard solution?
Is the solution old or new?
Can you confirm the phenol red is R-0014?

 

[tessv]

@justinc and @Donldson— hi!

1. FC is 8.5
2. I did confirm with white paper, just couldn’t hold them all and click a pic ?
3. Just received my solution from TFTests last week (could’ve been the end of the week before)
4. Indeed it is R-0014

 

[Richard320]

It does appear to read 7.5ish. This sounds like a job for @OTPirate

 

[tessv]

Thanks for the assist @Richard320!

 

[OTPirate]

Your FC is pretty close to being high enough to cause an interference with pH. If it is over 10 it will not give you an accurate reading. Test your R-0014 with one of the buffer solutions provided in your pH meter. If your ph meter is calibrated (use the two buffer solutions), then test ph with it. Have you done anything recently to lower pH, added muriatic acid?

 

[tessv]

Hi, @OTPirate! FC is lower than 10—8.5. Will test it again now, though.

I don’t have any of the buffer solutions that came with the pH meter (used them for the initial calibration when I got it)—which is why I ordered the 7.2 standard (thought it would be good to have around to be able to spot check)... another idea???

*I added MA twice last night—15-16 hours ago...

 

[tessv]

FC dropped some with backwash, top off, aeration (accessories have been running all morning), and heater on... 6.5 now...

(Have been waiting to raise CYA from 30 b/c we’re having the tanning ledge tiled sometime soon)...

Meter reads 7.0 now. drop test consistently reading 7.5...

Here’s a weird thing... just tested our RO water with the drop test... it’s a color I’ve never seen...

What the heck?? EDIT—tested the RO water with meter—get 8.5...

 

[OTPirate]

Do you still have two pH standards? Use one to calibrate your pH meter. In order not to waste reagent-pour the standard in a clean cup or something that the pH probe will easily fit into, calibrate then pour the solution back into its original bottle. You can use it again up to a year or so. Then test the other standard you have with your newly calibrated pH meter. It is unlikely both standards would be off. Then use the pH meter to test your pool pH.
What is the date on your R-0014? I'm thinking your CL may be high because you just added MA twice and still getting 7.5 pH. I have what i consider to be a large pool and I can drop my pH significantly with not too much MA. Did you use poolmath?

 

[OTPirate]

That color is indicative of high CL

 

[tessv]

So now I’m really confused! How/why would the RO water have High Chlorine??? (Another issue for another day, lol)

So, no—I only have the one 7.2 standard that I received last week... I didn’t know those solutions could be saved, or I would have...

Expiration date on R0014 is 4/20... (perhaps that’s a sign ?).


I really don’t think my Chlorine is high, BUT! Here’s another idea... I bought an API test kit at opening because we had lots of ammonia... it came with pH solutions—lemme run those and see what we get...

 

[tessv]

Ugh. That tested even lower than the probe... I suspect chlorine interference there, since it’s an aquarium kit... ??‍

Here’s me testing chlorine just now...

 

[ScottinTX]

Following this one....., I have 3 R-0014 samples, 1 that came in my TF-100 kit 6-7 months ago, 1 that came in a refill kit (exp 4/20), and 1 that came Saturday with other things I ordered (exp 12/20). I get 3 different pH readings ranging from 7.5 to 8 with these 3 R-0014 bottles. My FC is 5.5 (I think?).

 

[tessv]

Oh, and yes! I did use poolmath... I’m dependent on it! I was targeting 7.2, but it didn’t seem to budge, which is why I added more... The way I explained the lack of pH drop to myself last night was that because we had to add borax during opening (a tedious ammonia break caused a huge drop in pH), the Borax was really forcing the pH to hold...

Sooo—by pool math predictions, I should have gotten a drop of around 1.2 given the amount of MA that I added—that would place my end number near 6.6...

So, my meter reading 6.9 to start today seems closer to that... the aquarium test reads 6.4...

I don’t have a clue...

Water definitely “feels” on the acid side of things—just from testing today, that hand/arm are both super dry...

Told the kids not to plan to come swim today...

 

[tessv]

Oooh! @ScottinTX thanks for that! I’m questioning all of my procedures right now—hearing that you’re having a similar experience is comforting ?...

 

[tessv]

But—in the immediate—what should I do??? Try to find a ph test in town? I’m worried about running below 7, if indeed I am... I’m turning off the heater and cranking up the speed on the accessory pump for now... c’mon bubbles!!!

 

[ajw22]

Where did you get the 7.2 standard from?

Order a pH 7.0 standard from Amazon to be overnighted to you.

What pH meter are you using? How many point calibration does it have?

 

[OTPirate]

Where did you get the 7.2 standard from?

Standard Solutions

tftestkits.net

 

[tessv]

@ajw22, I get ALL my stuff from TFTestKits.... got the standards sampler and extra pH standard from them first part of the month... pH meter is the $12 one they sell—ordered & rec’d in March ahead of opening, along with my complete TF 100 refill kit... will order that 7.0 standard now...