Drop checker not matching manual tests
I'm fairly new at this and would like some help with CO2 readings.
I have a 29g, low light, moderately planted tank. I've just started dosing with the PPS Pro method and I just added injected CO2 with the Aquatek Mini Regulator on a paintball tank. I'm diffusing with an Aquatek 3-in-1 diffuser at 3bps and I'm sure I'm losing a fair amount due to running 1 AquaClear 30 and 1 Aquaclear 50 (both set to low).
Here's the dilemma. I put a Fluval drop checker in the tank 2 days before I started running the CO2. I used the premixed fluid that came with it. The reading was blue for the days I didn't run CO2. At the end of the first day I started running CO2 the drop checker turned green. Today it's still green and I tested PH and KH. KH was 8 degrees and PH was 7.5. I could be a bit off on PH due to it being hard to distinguish with the API test. These numbers mean the CO2 should be about 8. Am I missing something here? Even if I was off on the PH a bit I shouldn't be at 30ppm (turning drop checker green) until I hit a PH of 6.9. If it matters my GH is 12 degrees.
Please set me straight here! Thanks in advance!