I used the API 5 in 1 Aquarium Test Strips. It measures pH, Nitrate, Nitrite, Carbonate and General Hardness. I just did a 3rd reading and below are the results of all.
1st reading / 2nd reading / 3rd reading
Nitrate: 0 / 0 / 0
Nitrite: 0 / 0.5 / 0
pH: 7.0 / 7.5 / Appears between 7.0-7.5
KH...