I am currently trying to cycle my tank. I have a 5 gal fluval. I used live rock, sand, and bacteria. 2 clowns, cuc, a shrimp, and a royal gramma were added. I know I over stocked but I have a 75 gallon I am planning to convert to salt. Currently my ammonia is dropping but my nitrites are through the roof. My LFS said I could throw their old carbon pillow in my filter area to help boost some bacteria. Any reason I shouldn’t?