is this a requirement for a healthy reef? i have MH lights on from 10 a.m. to 9 p.m. at 9 p.m., i have an actinic light that comes on for about an hour. when it shuts off, my tank is in total darkness. i also have a little bitty moon light that i used before i got the bigger actinic. would it be ok to leave the little bitty moonlight on all night or does my tank need to be in total darkness for a number of hours? the little bitty one just casts a very faint shadow over the rock formation. my brittle star only comes out at night. would leaving this on disturb him? i asked but he refuses to answer me!