Ista Hydro Bio Sponge Filter looks cool. it seems like the other popular design of sponge filters. if It's quiet, thats good because this tank is in my bedroom and i have to sleep at night somehow haha! the HOB makes noise that i can take, so a quiet sponge filter is a plus.
What size do you recommend for a 20L? I want two of those to fit in the back portion of my tank, behind my plant scape.