So, I have my little 2.5 gallon and I took out the filter some time ago because it was blowing my betta around too much. I've added some java moss, hornwort, and a marimo ball to liven things up and help with the water quality, but the tank was still getting dirtier than I would like. I did an intensive cleaning yesterday (wiped down the walls, stirred and dipped to clean the substrate, etc...), and decided to stick the filter back in the tank because the water was still really messy. The water looks so much better, and I've noticed my ghost shrimp has started nibbling on the plant matter that's stuck to the pre-filter sponge.
I guess my question is, is there a way to baffle the filter a little better? I had cut up an extra pre-filter sponge and stuck pieces in the outflow but it's still creating more current than I would like. I know about the water bottle tutorial that's on this site, but I'm afraid it might be pretty bulky.
Are sponge filters terribly difficult to set up? I know they're pretty cheap, are there any other pros and cons?