pH Reading Check

[Sandstone]

Greetings,

Just got my TF-100 and digital meter and have a few questions:

1) what do you think this pH reading is? I say it’s between 7.8 and 8.2

2) it takes minutes for the digital meter to stabilize and if you stop stirring the reading increases. I find that odd but it’s not exactly a lab quality instrument.

TIA

 

[meatyor]

I’d guess 7.9

I don’t believe, though could be mistaken, that you’re supposed to stir the digital meter, because it does exactly what you said. I place it in the water and leave it still, usually takes about 30s to get a stable reading, in my experience.

 

[Mdragger88]

I’d call that inbetween 7.8 & 8.2 - its really not that big of a deal whether its 7.9 or 8.0 btw.
Lower it a few points if you wish and move on.
It will rise again lol

 

[Sandstone]

Thanks! It was late in the day and my eyes were tired from staring at my monitor all day so I wanted to confirm what I was seeing. The obviously translated instructions in the meter case say to "stir gently to wait 30 seconds" LOL but the TFP instructions don't mention stirring. I'll play with it.

 

[meatyor]

Yea, I think a couple stirs is all you need, but it’s hard to say

 

[JamesW]

7.6 to 7.7.

You go by hue and not intensity.

In my opinion, most people read the pH higher than actual due to this error.

You have yellow, orange, red and purple.

The hue means the color or shade or how yellow, orange, red or purple the color is.

 

[Gebo]

7.8

 

[Sandstone]

Weird...before adding dichlor I checked Cl levels and got 18 ppm FC, 1 ppm CC and the OTO test was clear. I actually added a 6th drop of R-0003 to to get a faint pint color before adding 2 drops of R-0871 to get the 1ppm of CC. I tested Cl a second time and got 10.5 FC and 1 CC (at 5 drops of R-0003). Strips show no FC and I haven't added dichlor since 6 days ago. That makes no sense unless the R-0871 reagent is bad. And I'm a chemical engineer so it's not like I don't have mad lab skills. Also I don't use MPS. I use sodium persulfate.

Alk 80
CH 150
pH 7.8

 

[JamesW]

I use sodium persulfate.

Why?

That will read as CC.

 

[Sandstone]

It was what was supplied with my spa. It doesn't irritate me or my wife but it bothers one of my kids who just graduated from college and came home with no job so I'm not trying to make it too comfortable for him LOL

 

[Mdragger88]

How old are your reagents?

 

[Sandstone]

I received the TF-100 on 8/2. The Taylor R-0003 has an expiration date of 4/26. There are no dates on any of the TFT bottles.

 

[proavia]

Try with a bit more back lighting.
Also, try with 4 drops of pH reagent instead of 5 drops. Some of us find it easier to e=read the pH result this way.

R-0014 is for the pH test.
R-0003 is for the CC test.
All reagents in the TF-100 are guaranteed fresh and should be good for at leastt one year.
Store the kit inside in a climate controlled area when not in use. Do not leave it outside or in the garage.

 

[Mdragger88]

to confirm:
you haven’t added any sanitizer (dichlor,trichlor,liquid chlorine, or otherwise) in 6 days but have instead added the sodium persulfate?

 

[Sandstone]

I haven't added either. It's been raining cats and dogs all week and I haven't been in it. After I use it I add 1-2 oz of non-chlorine shock depending on time and number of people and once a week I add 1-2 tablespoons of dichlor to hit 3-5ppm. The spa has never seen MPS in the 2 years it's been in service. Water was changed on 7/12.

 

[Mdragger88]

Please understand that non chlorine shock (mps or sodium persulfate)
are only oxidizers not sanitizers.
Chlorine is both a sanitizer and an oxidizer.
The majority of spas that see any use at all need more than 5ppm of fc per week to remain sanitary even if an oxidizer is keeping it looking clear.
If fc is below min for your cya at any time nasties will proliferate.
See—> FC/CYA Levels
There was an instance not long ago where someone was using a certain non chlorine shock & it also skewed the fc results not just the cc results. I haven’t been able to find it yet to link it.
At any rate, I suggest that you discontinue your use of “non chlorine shock ” products & stick with using liquid chlorine (if your cya is already 30+) as both your oxidizer & sanitizer keeping fc above minimum at all times & allow the oxidizer you have been using to dissipate. I suspect doing so you will see your test results will start to make sense.
* sulfates are not only irritating but also can damage your heater as they build up.
Most here only use them occasionally if ever. They are not necessary to maintain a spa in most cases.
Why use 2 things (oxidizer + sanitizer) when you can just use one thing (chlorine) that does both when used adequately?
I personally have never used non chlorine shock in my spa or pool and likely never will.
As a test of you may try adding 2 or 3ppm worth of liquid chlorine then seeing what your fc & oto results are.

How do I use Chlorine in my Spa or Hot Tub?

If you have a question about any information within this Sticky, please start a new thread for yourself where you will receive very quick responses to your specific questions. Thank you! Introduction There are two main things to consider when maintaining your hot tub water, Water Balance and...

www.troublefreepool.com

 

[Sandstone]

Thanks for the great info! My issue with using liquid chlorine is I need someone to add it when I'm not there. I don't want anyone spilling it on my cumaru deck or anywhere else but I guess I could leave a dose of dichlor in a small container which is what I do now. NaOCl is actually not that good for the acrylic and especially the structure which is why all premium fiberglass pools and spas have vinyl ester behind the acrylic or gel coat. Same with boats...vinyl ester behind the gel coat but that's just as a barrier coat for water which is an issue in itself.

 

[JoeSelf]

Try one of these for chlorine.