MH Height off of tank

[shoddy mac]

what is a general rule of thumb about height above a tank.I will be installing (2) 175 watt MH and a 96 watt PC on a 58 gal tank. Also how many cooling fans can you run in the canopy and which direction do they need to be blowing (ie. two in/ two out or all blowing out of the canopy?)

 

[mr . salty]

The bulbs should be at least 4" off the water.And the fans should be blowing in.That is if you have an opening for the hot air to excape.My canopy is open most of the way across the back.If yours is not,then you will need to balance the fans with an equal # pointing out to get the hot air our of the canopy...