Help!!!

[vaporlockv2]

My 150w MH light over my 28gal nano failed all together, replaced the ballast and the bulb and nothing weird right? Anyway a friend lent me his 400w metal halide I know that is over kill but I'm gonna use it until I get my new light in. How high should I keep it above my tank to first not fry my corals and not create a massive amount of heat problems.

[92awdGSX]

keep it as high as you can lol id say 2ft higher than the current easily. make sure to observe everything.

[prickles]

remember light has an inverse squared relationship. Therefore if it is 2x as far away, it will have 1/4 the light. If it is 4x as far away, it will have 1/16 the light. Therefore you should put your 400w about 1.6 times as far away as compared to your 150w. This is my remembrance of 10th grade physics...

If you are getting your new light soon, then be safer and leave it dark. Even reefs get hurricanes or clouds. It can be dark for 3-5 days. If it does go that long, then make sure to acclimate your corals to the light when you put it back on.