Ph Value Ranges for Strips

Hi all, I am trying to get myself some PH Test Strips.
There are broad value strips and narrower ones. either 1-14 or 2-5 for example.

Should I get various in different ranges for .5/.25 accuracy or are the 1-14 just enough?

Also I am interested in testing the following formulas.
What ranges would I need? 4-6 + 8-14?
Can I be sure that the solutions work just by their PH?
Can I be sure the solutions DO NOT work just by their PH?

-Dektol
-Maco ECOFUX(Neutral ph?)
-Adox Fix Adofix

Color:
-Tetenal BLIX
-Tetenal CD
-RA-4 CD/BLIX

Thanks for any INFO!

I seem to have gathered this values:
fix 4-6.5!-8 / neutral
cd 9-14
Blix 6.5-6.7
Dektol WS 10.2-10.4

At least for the critical colour processes ph-test-strips are not precise enough. Furthermore here the dyes of the strips might change due to other factors than ph.

Due to the color, it will be very difficult to get an accurate reading of any Bleach or Blix.

I restrict use to only developers. Use in the dark is impossible.

PE

Why do you think it is necessary to test the pH of commercial solutions? Manufacturers have very good quality control and it would be very rare that the pH would be incorrect. Even if the pH was wrong what would you do about it? In fact the average photo enthusiast has little need to test the pH of the solutions he uses even if he mixes his own.