I currently maintain 8 tanks, 300, 240, 180, 75, 40, 30, 20, and a 10, all are my tanks except the 30 with is the fiancé’s but I end up feeding and cleaning the tank. I recently got rid of my 135gal African Cichlid tank, this took me a good 6 months to decide if I wanted to get rid of it because I have had the fish for over 4 years, from little 1.5 inch Juv’s to full grown breeding adults. I was getting bored with African Cichlids so when I got rid of the tank there was an empty wall where I use to see my fish when watching tv or eating dinner. About 2-3 weeks after getting rid of it I got my 240gal, this tank is bare for ease of cleaning, helps reduce chances of burn out. My 300gal is the only tank that has décor, all others are bare, and the 180, 75, 40, 20, 10 are basically bare grow out tanks for fish that will eventually go in one of the two larger tanks. Going bare helps with less time spent on tank cleaning. In my 180 and 240 I have 1500gph Seio pumps to circulate the water and waste into the filter intakes so in the 180 I don’t really need to vac and should be the same for the 240, I just drain and fill. I also use a large device I made using PVC and pool filter hose to drain my 300gal to the half way point in about 10-11 mins, this would have taken about 30-45mins with a python, gonna try it out on my 240 either this WC or the next WC. Once I get most of the fish grown out I plan on having only 3 maybe 4 tanks going and not running the others. Another thing I have decided is figure out which fish I want to keep forever and which ones I want to maybe try out and sell, trade, exchange to keep things interesting. I also made a promise to the fiance’s that if one tank comes in one goes out, so this means I go bigger, which is what I did with the 135 to get a 240. Want to replace the 300 with a 600 or 750 in 2-3years.
I think the key is to figure out how much time you can dedicate to this hobby and figure how many tanks that translates too. You could decide you can maintain 4 tanks with décor or maybe 6 tanks with out décor, as well as taking into account the type and amount of fish you have in each tank. You could also cut back for a while and just maintain a few tanks and leave the other dry until you get the bug to try a new fish out or do something with the empty tank.