The goal of a sump light....

[LeviT]

Hey everyone. My understanding is the goal of a sump light is to stabilze tank parameters in the evening and maintane algea growth 24x7. So assuming that's correct what's the best light to get. I know a lot of people use outdoor lights from HD (or even cheapy clip on lights) or actual aquatrium lights. So what's the ideal balance of watage to be useful? I just have some live rock in my sump now and no chaeto or anything so it may be a waste.

Just looking for input and suggestions from actual experience.

 

[Gomer]

As you said, it is to balance parameters. More specifically pH. If your sump macro has a reverse lighting cycle, it will take in CO2 when the main is releasing it, and give it off when the main is taking it in.

The best light for growing macro algae would be a 5000 to 10,000K bulb. 6,700K bulbs are insanely common with planted tank people. ...but as you said, you just have rock. In this case, your sump is a nutrient export and should hardly be affected with by light. If you can toss in a wad of chaeto to grow into a mass, then you have something to work with.