so i wanted a 2.5 gallon sharing the water from my 38 gallon. so here are the pics, step by step as I did it.
my seltz L external powerhead
I made a little overflow box from a specimen container, with a sponge to trap any shrimp that get sucked in.
Here is the 2.5 gal
Here is the proximity to my main tank
Here is the placement of the pump and the overflow box
Placement of the rocks i got
Now just waiting to get some shrimps