With 3 tanks, I'm quaranteed to have some kind of a problem with at least one of them at a time, and sometimes all of them. I restarted in the hobby in late September. I seem to be going through the same stuff with each tank one or more at a time: first you get the diatoms, then the green algae, and then the cyanobacteria. Now that I beat the cyanobacteria, I got some fin rot in one of my tanks. Nothing serious, but after waiting a while with no meds, I finally decided to go for the antibiotics today, since new fish were getting it when the previous ones were cured from their slight cases. Then I saw some white worms in one of my tanks (apparently planaria, again nothing serious, but yucky nevertheless). After a while I realised I was having them in all of my tanks. Now that I just got over the more frequent water changes caused by the cyanobacteria, I have to start them again to kill the worm population, lol. I'm starting to realise that it's not likely all my tanks at any time will be 100% free from disease and all other problems . I haven't really had anything serious so far, and haven't lost a single fish (I lost a shrimp for something I don't know), but the tanks are certainly keeping me busy .