I would keep the old filter running together with the new one for at least two weeks. When I do something like this I like to supplement beneficial bacteria as well.I'm wanting to put a new filter (Penn Plax) on my 10 gallon fresh water tank but I don't want to mess with the water. I'm just getting finished with 3 weeks of ich x treatments too. What should I do???
I get where you're coming for when it comes to electricity. I only suggested running both to speed up the process. This along with a bio booster "BB" is almost a sure thing. Anyways I am just one person with a opinion on how things could be done. Fishkeepers for years have learned their own ways of doing things, and I respect that.Copy / pasted from your previous post : Is something wrong with the original filter? Are you still treating the tank / fish for ich? If you're still treating you do not want to use any carbon (Chemical) filtration , only mechanical and / or biological. Having 2 filters running in the same tank seems like a waste of electrical energy. (unless of course it's two 10 gallon sized filters in a 20 gallon tank or some such math )