Algae seems to be coming back

Hello All...

I seem to be getting a dusting of what the senior reefers here said was "the uglies." I am not sure why.

My numbers are:
Temp: 80
Ammonia: 0
Nitrites: 0
Nitrates: 0-10 (depending on the day)
pH: 8.0

Two ocellaris clowns
One banded sleeper goby
Three green chromis
One flame angel

I have a 23 gallon sump with bio balls, skimmer, UV sanitizer and a multimedia reactor running NPX bio pellets.

I have 23lbs of LR and about 1" bed of LS. It's a 92 gallon corner.

I bought an RO/DI machine and have been changing water about once every 9-10 days depending on work.

The fish are happy and eating. I also get some brown algae on the glass but not much. I scrape what I get. The brown on the sand went away a few weeks ago. Before the reactor I was getting some on the rocks. They are pristine now.

Any ideas? Thanks.