Hello all, I'm about 3 months into having my first reef tank. It's a biocube 32 gal. I have a royal gramma and 2 snails. Ive done multiple water changes and no matter what i do i cannot get my nitrates close to 0. It stays at about 20ppm. The other parameters in my tank are fine. I have a corralife protein skimmer and it's definitely picking up skimmate. Im not sure what else im supposed to do. I change the floss sponge in my media basket. Im hesitant to add chemicals and carbon if i really don't need to. Ive gotten a new test kit and it's reading the same. Any guidance would help. Thanks in advance.