I am having trouble with keeping my nitrates low. About a week ago my nitrate levels were at 40 ppm but now they are about 20 since i have been doing 5 gallon water changes every other day. I am thinking of getting rid of my substrate to help lower my nitrates even more, but is there any other ways I can lower it? I also moved all my live rock around the other day, could that possibly be why I have its high? I have a 38 gallon tank and I use the API testing kit.