I have a pretty heavily stocked 150g and am now forced to go bigger as I have fish that have grown very large. I agree with the bioload adding to the high nutrients as I’m battling this at the moment. There are several methods to reduce the nutrients though. The biggest thing to me as mentioned above is the amount of room the fish have to swim, suitable hiding spots, sleeping spots and overall how well the fish get along. The more fish the more competition for the few spots in the tank. You are always drawing a straw with a new addition to the tank. Slow and steady wins the race
