Learning to read PH.

[laurelru]

Hey there, brand new pool and first time pool owner. I have been following all the advice here and it's great. I am struggling with reading PH levels. I prefer a more specific number vs matching the colors like the test in the TFPro kit. This was my reading last night (picture 1) and with the help of others I guesstimated it to be 8.2 so using pool math I added Muriatic acid. I just rechecked (about an hr after) and the Ph has come down but what would you determine it to be now based on this test (Picture 2). Is there a more definite test that would appease my weird brain? Is there a trick to knowing the in between colors?

 

[ajw22]

Welcome to TFP.

What is your FC level? The pH test will read high if FC is over 10ppm.

 

[kimkats]

I got a white plastic plate (dollar tree) so I can hold it up behind the test. That helped me a lot to see the color to match it up. You can use a piece of paper instead. I like the plate is is easy to hold and just keep it under my test kit.

 

[laurelru]

Welcome to TFP.

What is your FC level? The pH test will read high if FC is over 10ppm.

3.5 (using my kit), my phosphates are super high at 1072 (Testing done at leslies), alk:80 , CA:450, CYA 35 (but leslies told me 55)

 

[ajw22]

1072 for phosphates is not high or super high. It sounds like a big number since it is measured in PPB - Parts per BILLION. While all other tests are measured in PPM - Parts Per Million.

Your phosphates are 1.072 PPM. that sound high?

When phosphates get to be 6,000 - 10,000 we can discuss high phosphates.

Don't fall for the Leslie high phosphate scam.

What did Leslie say your pH is?

 

[laurelru]

1072 for phosphates is not high or super high. It sounds like a big number since it is measured in PPB - Parts per BILLION. While all other tests are measured in PPM - Parts Per Million.

Your phosphates are 1.072 PPM. that sound high?

When phosphates get to be 6,000 - 10,000 we can discuss high phosphates.

Don't fall for the Leslie high phosphate scam.

What did Leslie say your pH is?

8.2ph per leslies. I was really good at leslies, not buying anything just tested and ran basically cause I wanted to a numeric value for the ph. They recommended their dry acid, Leslies Fresh & clear , and leslies no phos. Did not purchase any cause I already had acid and know from reading here not to buy things. I saw for high phos to get the orenda brand to lower them but do I need to even do that yet? Thank you for your help btw.

 

[ajw22]

I would agree on 8.2 or thereabouts.

Get your pH somewhere into the 7's. Exactly where really does not matter.

No reason to do anything about your phosphates.

 

[proavia]

Try using 4 drops of pH reagent instead of 5. Some of us find it easier to read the result that way.

If you can discern it's between two adjacent numbers, just guesstimate what the result is. Being off 0.1 or 0.2 isn't a big deal.

 

[laurelru]

Try using 4 drops of pH reagent instead of 5. Some of us fine it easier to read the result that way.

If you can discern it's between two adjacent numbers, just guesstimate what the result is. Being off 0.1 or 0.2 isn't a big deal.

Thank you!

 

[pjt]

Is there a trick to knowing the in between colors?

A consistent background is key. To get good backlighting, hold the block in front of your computer monitor/tablet/phone with a blank white screen displayed. Also, try holding the block sideways or upside down. Sometimes that helps distinguish colors better. I also use two old hotel keycards to mask off areas and narrow down my decision.

TFPro kit

Add that to your signature.

They recommended their dry acid

Use MA for pH control, not dry acid.

 

[zemurray]

I had the same issue at first. The 4 drops instead of 5 really helps. It's not the saturation of the color, but rather the hue. Darker red doesn't mean anything. If you notice the 8.2 block is leaning towards purple, and 7.2 block is leaning towards orange. Compare the tint to the blocks and ask yourself is it more orange, or more purple? That helped me. On your first sample, I would call that 8, second sample looks 7.7 to me. Test some tap water to see it get closer to orange for a reference.

 

[laurelru]

Me again.. PH testing is my nemesis Tested today and this is the result. I tried 4 drops prior and it still wasn't obvious to me so this is with 5 drops. I am guessing this is around 8? What would you say?

 

[ajw22]

7.8

It does not have the purple of 8.2

 

[mknauss]

I would call it mid 7's. No purple to be above 8

 

[Newdude]

Block off above and below what you want to compare and it's way easier. I use my thumbs but a cutout on paper or such works too. For example:

More pink than 7.8



Not quite 8.2 purple




Also, skip the FC test in the Block for now and use the powder test instead for an actual value.

 

[dereksanders]

Definitely closer to 7.8 than 8.2.

 

[AUSpool]

I started taking a photo and editing out everything other than comparator and sample colors. I’ve tried several different comparators over the years and have settled on my Taylor 9058. I was persisting with one for a while that had a fault where the 8.0 and 8.2 window had the same color. I cant tell the difference between your 7.8 and 7.5 windows. I would try another comparator.

This is the Taylor 9058.

And a cheapy that came with my startup kit.

 

[Woody007]

Is there a more definite test that would appease my weird brain?

I don't see folks talking about pH meters and I don't know why. I use one I had left over from beer making and it always compares to store manual method.

 

[AUSpool]

I don't see folks talking about pH meters and I don't know why. I use one I had left over from beer making and it always compares to store manual method.

There are plenty of threads discussing electronic meters, mostly handhelds. Electronic testers need calibration to two points and storage in a potassium chloride solution both of which costs money and takes time and even then the results can be skeptical. Old meters, poor calibration, cheep calibration fluids, incorrect storage, old probe, old batteries, etc. will all lead to poor results. People often confuse extra decimal places with accuracy. Without calibration an electronic meter is nothing more then a random number generator. And at the same time 4-5 drops in a pH comparator is more than accurate enough for most users.

 

[AUSpool]

To put some numbers to the potential error I pulled out my pH meter that’s been in the cupboard for over a year maybe. The storage solution had completely dried out. Gave it a rinse and a 5 minute soak in fresh KCl solution.

It’s a HM Digital PH-200. Middle of the road in quality as far as handhelds go I guess.

My pool water was reading 7.8 with the R0004 in the 9058 comparator. The HM R-200 meter read it as 8.1. In a Hanna 7.01 calibration fluid it read as 7.27. Calibrated it in the 7.01 and then in a Hanna 10.01 and it reads the pool as 7.8 and the Hanna 7.01 as 7.00.

So from my little test an uncalibrated pH meter thats reading to two decimal places can be out by as much as 0.2-0.3 pH units.