can't determine my CO2
As I wrote, I have a problem by determining my CO2. First of all I add Co2 with pressurized bottle of co2 and with PH controller.
I try to measure my PH, by take a sample of my aquarium water and let it sit for few days. I measure the PH and I found it 6.5.
I took again sample and this time, I put airstone for a hole day and I measured it 7.5.
WHICH ONE IS THE CORRECT WAY AND MY REAL PH???
During my day cycle, I start to inject co2 with my PH starts at 6.8 (i have a circulator hitting the surface all day) and I reach the PH to 5.95. My drop checker is lime green and I do the co2 dennerle test which is ok but i don't see my plants pearling a lot. when i'm trying to get the PH lower, my plants start pearling but my two small discus and my two leopard gurami search for air on the surface. The discus swimming like they are drank but the rest of the fish (red nose, cardinal tetras,blue gurami) are fine. My oxygen level, I test it with jbl test and is more than ok.
Is it possible some fishes to be more sensitive than others with the excess CO2? should I lower the PH or not.