I think you should definitely add more filtering. I've used multiple HOB filters in my life, nothing beats the AC110.. I love this filter, I have used them FOREVER.
Right now I'm running 1, set on the low setting, on a 22-gallon-cube-tank with 40-cardinal-tetras, water is crystal-clear.
I used to run 2 on a 45-gallon with 3 huge-ryunkin-pooping-machines, there the best HOB filter.
I've tried the bio-wheel-setups with dedicated angel-fish tanks to have less current in the tank, and the tank was always cloudy. Switched to AC110 water was crystal.
Can't say anything BUT GOOD with AC110's, (never used there smaller-models) but I'm sure they work well. I don't use the carbon, either 2 of the foam blocks, or one foam block and the rest packed with bio-media.