I try to be vigilant in regards to contamination/cross-contamination
*Any equipment that goes into or comes out of the tank gets a bleach bath before going into storage or back on the shelf.....nets, filters, tanks, heaters, etc
*For equipment that doesn't get disinfected regularly, I have dedicated equipment for each individual tank: water changing hoses, buckets, etc
*Water changes, water changes, water changes!!!! I do >50% every 3-4 days.
*Multiple filters on every tank.
*Heat controller on every tank.
*Won't ever use auto-feeders ever again. I just find that it just increases the chances of it fouling the water if it malfunctions. I don't trust people feeding my fish....from personal experiences and reading horrors stories online. I just let my fish go on a fast for 1-3wks while I'm away.....never had a single issue....never even seen a hint of a sunken belly
*Haven't used carbon as part of filtration system since the early '90s
*Won't use any sort of chemicals (clarifiers, algaecide, etc) in my tanks. I'm on well water, so I don't even have to use dechlorinator. I do use Seachem Safe, but only to neutralize equipment after a bleach bath
*Be vigilant during refilling the tank during water changes.....especially if you're multi-tasking. This mishap still occurs at least once or twice a year for me smh
I'd take this a step further, and seldom put my hands into the tank water. I do it when it is a must....and rearranging décor is not a must.