MH and heat

[jacksonpt]

I'm getting ready to build my canopy, and I was wondering about the heat from MH bulbs. I'll be running two 250w 7500k MH and two 40w NO actinics. How hot do the MH bulbs get? i.e. how much room do I need to leave between the bulbs and the wood, between the bulbs and the plastic stiplight for my actiics etc.

 

[mr . salty]

Those bulbs will get VERY hot.If you use a good reflector,they can be mounted within an inch of the wood.But only with a reflector between the wood and the bulb.Without a reflector,the wood will char,and eventually catch fire.As for the plastic,any plastic within about six inches will melt.But once again,a reflector between the bulb and the plastic will solve the problem.The bulb should also be at least 4-6 inches off the water...A cooling fan will also be needed in this hood....

 

[ivan]

I HAVE TWO 175W MH AND 3 40W BULBS TWO ATINIC AND ONE DAY LIGHT. I HAVE THEM 12" ABOVE THE GLASS TOP. I HAVE ONE 4" FAN COOLING THE CANOPY AND THE WATER TEMP STAYS AROUND 82. ALSO ITS NOT SUMMER SO I DON'T KNOW HOW HOT THEY'LL GET IN SUMMER. ANY WAYS I PLAN TO GET TO AC.S TO COOL THE HOUSE ALL SUMMER LONG. IS BETTER THAT GETTING ONE CHILLER AND WILL RUN ABOUT THE SAME AMOUNT OF MONEY OR EVEN CHEAPER. ALSO IF YOU HAVE THE TWO 250W MH I TINK YOU HAVE TO PIC THEM UP HIGHER OR YOU MIGHT BURN YOU CORALS. I'M NOT SURE HOW HIGH BUT SOME ONE ELSE MIGHT KNOW.

 

[ivan]

sorry about the caps.

 

[fishforme]

Just starting but I have two 250W 12k bulbs about 4" off the water using two Spider Reflectors. I have mounted two 4" fans in the canopy but with them off, I've noticed no temperature increases. Granted, I'm still cycling the tank and the lights are only on for about 3 hours at a time, but at the end of that 3hr period, I witness no temperature change yet. I plan to turn one and/or both on to minimize the temperature change. Oh yea, I tried to put in the glass top with plastic hindges, and the hinges started to melt. Bad...