If you're skimmer isn't pulling anything, then its either too big, you haven't run it long enough for the "break-in" period, or don't you have it at the correct water level.
I'm using the
Eshopps Protein Nano 10-35G Skimmer for my 29 and the cup is 2/3 full every 3 days or so.
I run around 80x water flow, a HOB filter, bag of carbon/zeolite, ESV 2-part dose, and I haven't done a water change in 3 months.
After using a canister for years, I know now they are a nitrate factory. Even if you clean it every week, you still have detritus sitting in the bottom for 7 days. That's by design. If you compare the volume of work that it is to disconnect, clean, add new water, clear the air/bubbles with the simple removal of the dirty media of a HOB that I can visually check on it anytime I want, it was easy to get basically 0 nutrients.