No problem. Most people just use the clip on lights you get at home dpot for like $8 and use a 6500 daylight squiggly bulb. I happen to use the macro grow 25 watt fixture cause I got in on a deal when I bought the sump. Macro doesnt need an awful lot of light to grow just light.
I run my refugium light opposite my day lighting. It;s supposed to help balance the ph I hear. Haven't noticed any side effects of running it that way though so I'll continue.
My macro has gorwn crzay over the last 3 months, mostly the caulpera, the chaeto is taking its time to grow. lol
I'm also doing every other week water changes now and my trates havent gone above 10 so far at their worst. Usually 5 or less so I guess its doing its job.