pH test a washed out purple

[mikech]

I'm getting a 'light', looks diluted colored purple on the pH test for almost 2 weeks now, making it difficult to read. If I add a few more drops it does shift to reddish, but this must be a false read. I know high FC can cause this, but that's not the case. I rarely have an FC above 7, and I let it drop to about 5 before adding chlorine, and get the same light purple at FC 5 as I do 8.

Full recent results are:

15,000 G Pool
Temp 69F
FC 7
pH 7.5 - 7.7 ??
TA 60
CH 370
CYA 50

The only 2 things I can think of are that I added some pH Plus (Pinch a Penny) that I bought when I didn't know better ages ago (I rarely have to increase pH but I added too much acid by accident). The second is that I opened up a new bottle of Taylor Phenol Red (purchased from TFTestkits) at the same time. I used it first after adding the pH Plus.

Any thoughts?

Mike

 

[duraleigh]

ages ago

How long is that? Your reagent could be bad, especially if left in the sun for any length over about 30 minutes.

Even if the above is correct, it still looks like your pH is too high. Go to pinch-a-penny to see if they get "purple", too. If so, lower your pH with muriatic until you get it in the mid seven's.

Check your reagent's age...........anything over 18 months or has been in the sun should be replaced.

 

[JoyfulNoise]

Your K-2006 kit comes with Acid Demand reagent. What happens to color when you add the acid demand drops to your pH sample?

 

[mikech]

How long is that? Your reagent could be bad, especially if left in the sun for any length over about 30 minutes.

Even if the above is correct, it still looks like your pH is too high. Go to pinch-a-penny to see if they get "purple", too. If so, lower your pH with muriatic until you get it in the mid seven's.

Check your reagent's age...........anything over 18 months or has been in the sun should be replaced.

The pH Plus (Suncoast brand) was about 2 years old but always kept in the dark, and it is probably just Borax anyway. The Phenol Red was brand new from TFTestkits

- - - Updated - - -

Your K-2006 kit comes with Acid Demand reagent. What happens to color when you add the acid demand drops to your pH sample?

I'll try that tonight - thanks

 

[JoyfulNoise]

Any updates? Were you able to see a color change with the acid demand drops?

 

[mikech]

Any updates? Were you able to see a color change with the acid demand drops?

I added 2 drops and it went almost clear, 3 and completely clear. I can only get a matching color if I add 8 or 9 drops of R-0014 Phenol Red on a normal test. Doing this, I get about 7.8, so as a test I added enough acid to bring it down to 7.2, which should be an obvious color change. Adding 5 drops Phenol Red again gave a washed out yellow/orange, adding 9 brought it to a match. Could I have a bad Phenol Red although it was new? I'm going to let it drift back up to 7.8 /7.9 and repeat.

 

[duraleigh]

Phenol Red will be destroyed quickly if left out in the sun. That's about all that can go wrong with it.

Contact TFTestkits ([email protected]) and tell them your name and when you bought it. They will ship you a replacement,

 

[OTPirate]

Wait. Are you using R-0014? If you have the K-2006 you should be using R-0004 for phenol red. They are both phenol red, but in different strengths. You will get an incorrect pH reading if using the K-2006 comparator with R-0014

 

[JoyfulNoise]

Something is not right here.

The K-2006 kit comes with R-0004 phenol red and the large comparator block (44mL pH test sample). It also comes with R-0005 and R-0006 acid and base demand reagents. The R-0014 phenol red reagent only comes in kits that use the smaller, midget comparator block (4.5mL pH test sample).

Under no circumstances should the pH test go from colored to clear. The pH test reads shades of color that transition from yellow/orange (acidic or low pH) to red/purple (basic or high pH).

Please take pictures of what you have and what you are doing and post them.


Sent from my iPhone using Tapatalk

 

[mikech]

It looks like I have the wrong Phenol Red. Tftestkits are sorting it. My bad for not checking the label sooner. And it was my error when placing the order.

Mike