Green leaves popping up on live rock

[rogair]

I've been keeping this nano for about a year now and these have been popping up within the last few months. Some kind of algae? Caulerpa?
I want it gone!

IM Nuvo 8 gallon
Ledtric par 38 full spectrum
Filter pad - carbon/GFO in filter bag
Water change every week - 10 days ( 1 gal)
Tunze 1073.008 pump (spinstream output)
Just recently added a nano koralia ph for flow.
I checked nitrate = 0 (ELOS)
Phosphate = 0 (API....)
RODI 0 TDS - Reef crystals.

Here's some pics from my iPhone.