+1 on this. Depending on your setup, you are probably sending your tank into mini-cycles.Changing the filter media? I am no pro but wouldn't this mean your tank would than be uncycled?
You have no top on your tank and your fish disappeared completely. 1+1= they are now floor jerky.Okay I will do. Filter media gets changed every three weeks and the filters get a complete cleaning about every two months. I have no top on my tank so the water evaporates pretty fast and I just refill it with a 5 gal bucket. I would say 20% of the water gets evaporated and replaced every week