why?

SHOULD I CHANGE FILTERS AFTER CLEANING MY TANK.

Nope. That would not be a good idea. I am glad you asked first. Changing the filter will cause you to lose all your good bacteria. This will likely send your tank into cycling mode again. If your filter media gets dirty do not clean it all at once. Just rinse part of it or if you have one of the filters that uses multiple filter cartridges or media then just change out part of it. Change out the rest a couple weeks later once the new stuff is established with bacteria. If you cannot do this then you may be able to change out all the media if you have enough other surfaces colonized. This would mainly be the gravel. I guess I am trying to say it is a risk that you should not take unless you have to.

u change filter? then u loose the bacterial colony in ur aquarium

Welcome to the Forum!

I have to agree. I wouldn't change the filter media.

Now that being said... If it's really nasty... You can change part of it, like Meg said.

If you have the bags that have the charcoal in them, the reuseable kind, you can take one out, remove the charcoal, rinse the bag in tankwater, rinse your charcoal ***BEFORE*** putting in the bag, then put it in the bag and back into the filter.

Good Luck!