Hi,

I have a 6-month old 55-gal heavily planted tank and I inject CO2.
I've been running filterless since the beginning, but would like to
add an external filter of some kind to provide mechanical filtration
and water movement.

Any suggestions? And what turnover rate is recommended?

Also, do any of you utilize any type of chemical filtration in your
planted tanks (carbon, Chemi-Pure, Purigen, etc.)? Is this needed? I
guess a better question might be whether or not there exists a
chemical medium that doesn't remove the vital goodies from the water
in a planted tank..?

Thanks!