Dad picked up a Top Fin 5.5 setup from Petsmart for under $30. Here is a photo of the 5.5 setup along with the smaller critter keeper "mama fish" is in.

The filter is surprisingly quiet and the flow looked tame until we added fish, lol. We made a bottle baffle; I'm not sure how much it helped but there seems to be enough still water for the minnows to hang out in. We have to turn the filter off when we feed them. The plants are from the canal, and I didn't bother rinsing the rock or the krusty krabhouse so the snail would have something to eat.
The filter (Top Fin Power Filter 10) has a filter cartridge (carbon in a floss bag), and a plastic frame with a piece of very porous black foam (feels like a plasticy sponge). The foam is mentioned once in the set-up instructions, but not again in any of the very minimal maintenance instructions. It sits in front of the filter cartridge, closest to the output. Is the foam where the good bacteria is supposed to grow? Should I replace it with something better? Should I post these questions in the freshwater equipment forum instead of here?
I pulled a handful of what I think is hornwort out of the canal. I'm attaching two photos. In the second, close-up photo you can see a translucent bump that I'm assuming is some kind of egg, can anyone identify it? I picked through and pinched off as much as I could, which resulted in a somewhat denuded strand (I got tired and left the rest in the bucket). I put it in "mama fish's" tank to keep it separate from the main tank for now, in case I missed any eggs. Last thing I need is to breed mosquitos or some other pest inside my son's room!
Also in the close-up you can see tiny dark bumps all along the strands of the hornwort. I can't tell if these are foreign, or actually a part of the plant (like buds on a stem). Can anyone tell me? If they are NOT part of the plant, I am throwing it back into the canal before we get infested with something!
Finally, I'm attaching a photo of another plant that grows in the shallows of the canal. I rinsed and pulled off as much black gunk as I could before adding it to the tank. I've had a (different) small clump of it floating in the critter keeper for three weeks so I figure I'm good to go with that.
While harvesting plants yesterday we discovered the shallows teeming with tadpoles. Yet another nature study project… but I am definitely not taking those indoors!!
Thanks so much again… and again… and again.
