[Tagar89]

So i have read about cycling and to make sure you do it when setting up a tank. but im getting ready to do a water change for my tank and was wondering if you tank has all ready cycled, would doing a water change take any of the benifishal bacteria out?, or just what are the do's and donts on a water change?

Sorry for all the questions but im really getting into aquariums. Im one of those guys that when i get into something i study it and try to do it perfect (nerd lol) anyways thanks guys.

 

[StevieT]

The bacteria is in the rock, not the water. Do a 20%-30% WC if your cycle is complete. Wait a week and test again. Then do a 10% WC. If everything is good add a small CUC

 

[Dmaaaaax]

The bacteria is in your rocks and filter. You can do a small water change (10-50%) and vacuum some of your gravel (50%) each week and should be fine. Just don't vacuume all of your gravel and change your filters at the same time. This could lead to a mini-cycle depending on how stocked your tank is.

Always treat the new water with a dechlorinator/ammonia remover like Prime.

 

[Oldman]

If your tank is properly cycled you could do a daily small water change, like 50%, and the fish would be fine. People who have fish that are very sensitive to the chemistry of their water do just that so that their discus and similar fish can thrive. I am personally too lazy for that much water change but I don't hold back for the fish's sake, I hold back because I don't think that much is usually needed.