refugium lighting question...

[reefmut]

i just installed a n ecostystem type refugium under my tank and the type of macro is feather calupera. the sump section is app 20 gal. i just installed a 2x20 watt fixture with ge aquarium grow lights . i am going to add one more fixture of this type bringing total wattage to 80. how far should i put the lights off the waters surface??

 

[danmhippo]

As low as possible as your light might not have a good penetration into the water. Put it low enough to keep salt sprays off.