Hiya
When I had a 10 gallon aquarium fish tank, I used an aqua clear 20. Usually when I switched to a new filter. I just put in the new filter to run along with the old filter. I usually turned down the old filter to a very slow moving water current, and kept the new one at a regular flow.
It worked for me, but I only had goldfishes and a pleco back then. So the new aqua clear worked better than my old pet cetera one... ugh the other one demanded so much cleaning, and ran up my electricity bills a bit... but oh well.
So it took me about one week before I could take out the old pet cetera filter. I gave it away to some family who was looking for a used filter
So my best thing to say is. Be careful on what type of fishes you have.
Smaller fishes like tetras, and guppies or mollies are very delicate and can PROBABLY get stressed out very easily.
So use caution.