ph measurement

Terra aquatica got a super drip test for ph I really recommend this one bottle costs 5€ and you can check withit 500x

You can get a proper pH pen for under ten dollars. You can usually get both a pH pen and TDS tester for less than fifteen. Don't monkey around with drops or tricks when the real thing is so cheap.

An electrical tester is not very expensive, but there are also PH strips that exist if you want ✌️

purple cabbage water is a PH indicator. blue for bases and pink for acids. purple for neutral. but disconcerting trying to put a real number to it.. PH strips are cheep and the pool ones have two or three indicators to help resolve the differences in PH. These are the best options IMO next to a PH pen. I use a shity 20$ one and it works well for me. but strips you never need to calibrate, just store them well and they are good x amount of months after opening. amazon or other places have them. look for places that sell pool supplies.