I have a 45 fw
tank. I test the water weekly and the Nitrate reading is always 40 ppm
Last week I opened new Nitrate bottles and my Nitrate reading is 20ppm.
I tested twice and I got the same reading.
I'm glad the Nitrates tested lower but why when nothing in the tank has changed? Same fish, same amount of weekly water changes, etc.
The old bottles ran out, they weren't expired.