API and Aquarium Co-op test strips question

[Stroy15]

Hello everyone, I filmed a time-lapse of API changing color when I was testing the tap PH during a water change at first it reads 7-7.2 then drops to 6.6 or less and the test strip reads close to 7.2. Is this due to gassing off or differences in how these methods measure PH?

I don't know which is more reliable.

https://youtu.be/GYYLjk_UH1o 

[Guppysnail]

Both. 
7.2 is most likely accurate on both. 
PH on api test you shake and read immediately for accuracy. I assume the instructions say read immediately because they know as it sits for awhile the accuracy dwindles. 
Hope that helps. 

[nabokovfan87]

From my own experience, it is pretty important for me to set a timer or at least attempt to keep in mind the time for the testing.  The main goal is to test accurate, interpret the test accurately.  Time is definitely a factor.

On 6/5/2023 at 2:17 PM, Stroy15 said:

I filmed a time-lapse of API changing color when I was testing the tap PH during a water change at first it reads 7-7.2 then drops to 6.6 or less and the test strip reads close to 7.2. Is this due to gassing off or differences in how these methods measure PH?

Watching the video....

Can you elaborate on which test is which?

[Stroy15]

On 6/5/2023 at 8:37 PM, nabokovfan87 said:

From my own experience, it is pretty important for me to set a timer or at least attempt to keep in mind the time for the testing.  The main goal is to test accurate, interpret the test accurately.  Time is definitely a factor.

Watching the video....

Can you elaborate on which test is which?

I used the API liquid test and the aquarium co-op strip test which I think both were shown in the video. All tests was for PH. I completed the water change without fiddling with PH because I decided the tap was 7.2 and my guramis are at least satisfied with it and fed with frozen food.

In other news I have identified at least 3 baby red eye tetras in my other tank which is neat.