I have an outdoor socket from christmas, the green type with a stake, but I have it hanging over the sump, and a 23w compact flurescent spot light bulb attached to it. The chaeto certainly grows but I'm sure there is room for improvement. Mine may also need more flow, as its in the same chamber as the return pump without a seperate flow through area. Dowtish how is that 3800k LED working? I may want to look into replacing mine with one of those if its an improvement, when its time for a new bulb.