yes al lights will "grow" chaeto even that incandescent bulb u buy from ur local hardware store it just does it super slowly so slow it wouldn't be effective or as effiecient (im talking abt the incandescent rn) the light u have on the us a horticulture light with reds, UV, blue (actinic) and will obviously do a much better job then the incandescent
long story short: all lights grow chart but the better the light (intensity and spectrum) the faster it'll grow it meaning the charts will remove nutrients faster (more efficiently and effective')
600 watts is a lot of power for a refugium light. We are using one 14watt for the algae scrubber & one 9 watt generic plant LED bulb for phytoplankton, sea lettuce & chaeto. All of this is in our refugium & attached to a manual timer for 16hrs on, 8 off.