DO NOT pH before you add your nutes... pH'ing should be one of the last things you do right before you feed... adding nutes will change the pH of the solution every time.
Are you taking a "new" sample again every time after you add pH up or down? Or are you trying to test the same old sample in the little vial?
The ph drops are accurate, raise your ph to 5.8... which will look on the orange side of yellow in a clear shot glass against a white background in MH or CFL lighting... holding it up in hps lighting should be good enough too.
If you have the orange tinted test vial, I wouldn't recommend using it. Once you know what 5.8 looks like, you can always refer to the drops as a second opinion if you suspect your ph meter is off, because they should be pretty accurate.
i only have a 2L nute solution not 1gal. everything is 1/2d and ive got the clear vial. but I've added 10ml of ph up and no color change?
10 ML of pH Up isn't shit. It takes a lot. BUT adding it directly without dilution can cause immediate lockout from what I have read numerous times. Don't know how but it supposedly does. Best pH Up is tap water. Empty the res totally. Fill with water and 1/4 strength of recommended, not 1/2. Test and adjust accordingly.
Yes, you can force a shock-type lockout with a pH spike, it'd be temporary, but you really dont wish to stress your ladies in that respect unless it's drastic and you really can't help it. I agree completely with 1/4 strength as well, with a complete res cleaning and test.
What is the water pH with no nutes in it whatsoever? Is the originating water from well or through the city? Is it RO? Are you filtering it in any way?