Skimmer or Chaeto

[tunachunks]

I had to make the same decision a while back. And I ended up using all the space in the sump for cheato, I am also using a HOB skimmer that has a much smaller footprint. It hangs off my sump, and runs 12h per day.
Not sure if the Skimmer is needed, I had the system running without it for 3 weeks with no ill effects. But it gives me piece of mind.

If you had a big nutrient spike, like when something dies in your tank the skimmer would take care of it. That is my argument for still running it.