Hi, I am hoping someone can help me get to the bottom of why I am getting such high Nitrate Readings. I have a 300 litre high tech tank and am adding 25ml TNC complete a day, This equates to 1.25PPM Nitrate daily. However, using an API test kit the Nitrate Readings are 80ppm+ only a couple of days after a 75% water change. The tank is moderately stocked so I cant understand where all these Nitrates are coming from. Can anyone help?