Hi, I am new to the forum and I have a few questions. I currently have 3 setup tanks. A 10 gallon, a 20 gallon, and a 40 gallon. I got the water tested in my 10 gallon. I found out that my nitrites were around 3 ppm. I have a yellow lab (2 in), a small frontosa (2 in), and a small lab which I...