ok, so i had trouble with nitrates for my 90g, which currently has a 9" RTC, 2 8" oscars, and a 5" jd, but i gave away my 14" gar and 2 red devils i had due to advice i was getting about how overstocked my tank was, and for some weird reason, last night i read between 40 and 80 ppm nitrates soon after a 35% water change, and today, im only reading between 5 to 10ppm nitrates. As far as I know, nitrates only go away through water changes, and i asked my whole family if they changed the water, though they never do, and no one said they did, so i have no idea how nitrates could have dropped. the only thing i can think of is there seems to be some relationship between nitrates and alkalinity and pH, and i know this tank has very soft water and low pH, but does anyone have any idea how this could have happened? I tested the nitrates twice today and for sure they are between 5 and 10ppm, closer to 5. this just makes no sense to me. it was good to give away the gar since he was 14" in an 18" tank, but i miss the red devils and am starting to think i gave them away prematurley if this is the case.
