want to clean my wisper 2-5 with chlorine, because my poor fish were suffering from frequient illness, and I think that it may be because of bacteria, fungus or parictes being trapped in the filter despite frequient medicating and cleaning. Can I clean my filter by filling an empty taink with water and a small amount of chlorine and let it run for a few days, then clean out the tank and filter and fill tank with water and add chlorine nutralizers, then let it run for a few days? I know that this sounds risky but dose any one think that its possible to do this and still use both tank and filter for fish again.

yes you can, as long as you make sure all the chlorine is out. I wash used tanks I get with chlorine, and my fish are fine.

I was thinking that you'd kill the beneficial bacteria with it, but I guess killing the bad ones are more important.

I have got larger tank that is set up so I probably will remove the artificial plants from it into the cleaned tank when ever I am ready to put fish in it.