API test kit for PH

[SandNukka15]

So I have 2 api test kits from API and while testing my tanks PH I used both high ph test kit and low ph test kit. For the low ph test kit it read 7.6 which is the highest on the chart and for the high ph test kit it read 7.4 which is the lowest on the chart. So what's my ph?... this happen to any of you.

I tested the ph from my tap and it read 7.2 so I know the test kits are at least working.

 

[Ulu]

The results aren't accurate at the top of the low chart and the bottom of the high chart.
You're about 7.5

 

[duanes]

Where I worked in a water quality lab, we had 3 kinds of pH gradients, and used 3 standard reagents for pH in strips, colorimetric (like API) and when using pH probes , and each would be used for the type water that was expected. low end 3-7, neutral 5-8. and the high end 7-10, Most aquarium tests did not need to require the kind of detail and accuracy we needed, so (just like the API I use now, you and I are getting a ballpark figure like Ulu suggested. If you want real accuracy, you will need to go to a EPA water quality version provided by lab suppliers like Fisher Scientific, or some other lab supplier with EPA/DNR requirements, and quality control. (and the cost of that quality will be reflected in the kit, or probe), although todays generic technology may have crept up leaps and bounds since my lab days over 5 years ago.
A blackwater pond test near where I live now, below, it is really probably lower, could be on the 5+/- range