can u do to much water change

I change mine every week, doing the same percentage, same teaspoon salt, same temp water going back in, etc. They seem fine with it. levels are all fine.

As to your question can you do to much water changes. The answer would be yes. If you change your water everyday lets say 40 % your biological filtration is going to die off because it does not have any nitrites to eat up. then if that dies off your amonia is going to spike depending on how many fish you have in your tank, but it will happen sooner or later. If all this occures you are going to have to re-cycle your tank and your fish are not going to be happy reading the other replys people might say I am wrong but if you do that then you will have to learn for yourself.

The Nitrites will eventually go to nothing. If you test your water and the nitrites are way to high. What do you do? A water change to bring it back closser to zero. So over time of doing this water change everyday or even every other day will will go down to no nitrites then there will be no nitrates because thats what eats the nitrites. Then there will be no biological filtration going on. I really don't want to argue, I am not saying I am an expert, take what I say with a grain of salt if you don't want to listen. But, I have been doing alot of reading on cycling tanks, and came across some articles of dealing with having to re-cycle your tank because people did to many or to much of a water changes. I think personally If you did 2 water changes a week if you really want to spend that much time doing 20 to 30% would be fine, or you can do 1 a week of 30 to 40% is good.