A lot of people just buy lights from home depot. Just research it. I use a fluval led
but I'm not sure how well it works in comparison to other people's set ups. I just installed it a few weeks ago. I haven't seen significant growth but my nitrates are basically 0 and my copods are doing well in there. I used about 1 inch of refugium mud with a 1 inch aragonite sand bed over the top. Keep in mind if you use mud you are supposed to change 50% of the mud every year. Some people use a deep sand bed in there refugium and some go bare bottom. Just research your options and pick what you think will be best for your set up.
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