Hi, I currently have 75 gallon tank that has been running for about 3 years. I was wondering if it is necessary to run a GFO/Carbon reactor. I have been reading up about them and I have mixed thoughts on what I should do. :crazy: I currently run carbon in a bag and leave it in the sump. I was also wondering how many of you guys do use reactors for biopellets, gfo/carbon, and calcium. I have read up on what what each reactor do, but I am having mixed thoughts on what I should run any in my tank. Any opinions would help me alot, thank you!