Ok so, I just did a nitrate level test and it read a 41ppm. So decided to a 30%ish waterchange. I opted to put a few mls of API quickstart n stresscoat adjusting to the 30% new water. For some strange reason, the nitrate shot up to 50ppm.. Wth is going on? My tap water is only 15ppm-ish.. What causes nitrate to rise in general and in my case? I added more quickstart n stres coat. Do I need the filter to process more of the water? Please help me out... I need to control the level ASAP! Thanks so much for the help!