How much light is required to light macro algaes in my sump? At present I have Cheato may add other things later. I have a 20L for my sump and a 36" Marineland with 3 blubs 25w each for the light at 8 hours daily. I think the bulbs are T8s and of unknown age. I'd like to place the light up and out of the way. Like in the pic.. But if it needs to sit on the tank so be it. Its about 12" from the top of tank to bottom of upper cabinet rail, so there is that to work with.

You can get by with just a regular grow bulb and a desk lamp if you had to. You could mount a light on a clip and use that if you wanted too. Chaeto and most other Macro algae to put in a sump really don't care what light it is, as long as there is light.