Having trouble measuring ph
I've got an API freshwater testing kit + GH & KH. I'm having a hard time measuring the ph of my water. I know my well water is around 8.2ph with a GH & KH of 12-14. That's high enough I can pick out the color change. But I've got a RO unit and using a 75/25 mix of RO & well water. And that's where the problem is.
The regular API ph looks bright blue which the chart says is 7.6+. The high ph test is difficult for me to read. It looks like a tannish / brownish / tea-like shade that doesn't really fit the scale. Might be the 7.4. But as I move around to different lights, go outside, use a sheet of white paper, etc etc.... it might be 7.4. Then again maybe it's the 7.8 or the 8.0. It's so easy to change that shade.
Anyway, I'm trying to see how low I can lower my ph without having to remineralize. The 75/25 mix has my KH at 5-6 which seems ideal. But the tank will hopefully have cardinal tetra and a bolivian ram (and other less sensitive fish), so I'm trying to get my water closer to the parameters they enjoy.
Are there any other kits that are easier to discern?