Ph And High Ph

[dipsydoodlenoodle]

What is the difference?

 

[chesterjohn]

ph will measure a certain range of acidity in the water. If it is at the top of that scale, then use the ph high to measure the ph

 

[dipsydoodlenoodle]

That is what I thought, but I wasn't sure (I assumed that they'd just make one that measures everything lol).

Thanks

 

[Fish_Man43]

I was a little confused over this high and low, as every time i do a test with API the pH it's on the last colour blue so used the Ph high and it's on a very pale brown so not to sure what my pH is as it's not as dark brown as 7.4 on the chart, so i think it might be 7.2? but i have noticed that some colours don't match up like the nitrite as mine is a very pale blue lighter then the blue on the colour chart, does anyone else have this problem?

 

[JoshuaA]

I was always wondering how come they never just sell a bottle of universal indicator in the fish stores? I assume its due to the fact it's not that precise when coming to read on the colour chart for small .2 increment measurements?

I was a little confused over this high and low, as every time i do a test with the pH it's on the last colour blue so used the Ph high and it's on a very pale brown so not to sure what my pH is as it's not as dark brown as 7.4 on the chart, so i think it might be 7.2? but i have noticed that some colours don't match up like the nitrite as mine is a very pall blue lighter then the blue on the colour chart, does anyone else have this problem?

I know what you mean, I get the same with the API test.

I believe its due to the tests becoming less accurate at the extreme on both ends of the scale. The normal ph becomes a little less accurate towards the upper end and then you use your high ph which is trying to measurement at the extreme low! I think its a matter of guess work with that one, or you can just average the readings out and assume thats what you have!

^ However don't count me on that, that is purely my "educated" guess.

 

[meguro]

they dont use universal indicator as there is no need to measure 85% of the scale it covers. u really only need to be able to measure between about 6-8, anything outside that is virtually unnecessary

 

[chesterjohn]

7 is neutral ph, and from what I remember, that's about the top of one scale and the bottom of the other. So I guess to get an accurate result for small ph changes as we require, they have 2 different types of test, one for alkali and one for acid rather than a general test.

If it's over the top of the ph scale and under the ph high scale, then it's somewhere between the 2, I'd just interpolate between them as JoshuaA says.

 

[OldMan47]

The test ranges overlap a bit so if you are the end of one range, it is best to try using the other test too. In my own case I call my pH 7.8 because the high range sits at 7.8 and the "normal" range is at the top of its ability to measure.