Originally Posted by rreekers
How often do you do waterchanges?
how much water do you change out?
how big is your tank?
(if you want to share) what is your stock?
This is one of my favorite tank subjects. If you're getting out the equipment for doing a water change, then I suggest you make it worth the effort.
The reason is your fish are living in their own waste products and need a constant flow of a lot of clean, treated water flushed through the tank regularly. A 25 to 30 percent water change isn't much better than no change at all.
The reason is that the ammonia, nitrites and nitrates build up in the tank every minute and the longer the pollutants stay in the water, the more it weakens the fishes' immune system. That's the reason, tank keepers have issues with sick fish and deal with parsites like "Ich".
I change 60 to 70 percent of the water in my tanks every week. By doing this, there's no time for pollutants to build up in the water before the next large change.
I learned a long time ago, that the more tank water you change and the more often you change it, the healthier your fish and plants will be.