I have four tanks. A 120 g FOWLR, a 75 g reef, a 47 g clown, wrasse and Zoa tank and a 20 g quarantine tank! I work from home so it’s not a problem taking care of all four throughout the day! The only thing that I have that is automatic are my ATO’s! I don’t use dosers! I check parameters a couple times a week with the Hanna HI97115UC checker and I manually dose Alk and Iodine! If needed I dose magnesium and calcium as well! Two tanks in my office, one built into the wall in my living room and my quarantine is in a walk-in closet! The only real con that I see is rising costs in everything that is purchased! Other than that, it s not a problem with multiple tanks!