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1FishTwoFish
10/06/2014, 09:04 PM
I'm thinking about running an old 250w halide over a new tank setup. It was retrofit into a canopy before but it will be setup as a pendant now. There will be plenty of open space around the bulb and the reflector is a cooling fan necessary to prevent the bulb from running too hot?

maddmaxx
10/06/2014, 09:09 PM
its not really the bulb that you want to cool down. its usually the area the bulb is in so that way the bulb doesnt heat up the air inside the canopy, which will heat up your water.

Mr D smack
10/07/2014, 05:20 AM
Im running a 250w over a 30 gallon tank with no fan. Heat hasn't been a issue on this

Bpb
10/07/2014, 08:10 AM
Yeah halide bulbs run super hot no fan will cool them down. Fans do a tremendous job of cooling the water. I have a single 6" fan inside my canopy over my 90 gallon with 2x250 watt halides and when the fan turns on the water temperature will drop 1.5 degrees in about 30 minutes

1FishTwoFish
10/09/2014, 10:57 PM
I read somewhere that the overheating of bulbs could cause shorter life of the bulb itself so that was my main concern. As for the water temp I'm not too worried as the tank will most likely be open top, in a room where the ambient air temp never exceeds 74* during the daytime and 70* at night. I'm also planning on using low wattage pumps to cut down on heat transfer. If anything I may to consider heating the tank which I would like to avoid if possible thanks to a couple major heater failures in the past.

williewilliams
10/10/2014, 08:10 AM
worry about tank temp! It will heat up the water no matter the fan or not. I run 2 tanks with 2 250w MH and 4 54w t5 on both and the water temp changes when the lights come on for sure. not matter open top or not. I dont run a chiller but more of a radiator for the tank.

Bryopsis
10/10/2014, 08:39 AM
I recall when I had 2x150w MH's and a couple t5's over my 75g, it would heat the water about 4-5 degrees.. Open top, fan in the unit..

cloak
10/10/2014, 10:44 AM
I'm thinking about running an old 250w halide over a new tank setup. It was retrofit into a canopy before but it will be setup as a pendant now. There will be plenty of open space around the bulb and the reflector is a cooling fan necessary to prevent the bulb from running too hot?

I think you'll be ok without a fan, but if heat does become an issue, it should be real easy to alleviate with a common household fan. (especially a pendant)

1FishTwoFish
10/11/2014, 09:21 PM
I had a tank setup in this room before with an open top but was using t5's and had alot of evaporation going on from all the airflow in the room. Large ceiling fan and Window Ac so I think I should be good as far as Tank temps go. I'm going to try and avoid a heater if possible. I lost over $8k in livestock when my old tank had a heater malfunction. These animals are worth too much, not only financially, but environmentally to risk losing over a heater. The other tank that was in here stayed stable at 72-74

Mark426
10/12/2014, 06:12 AM
Maybe think of using something other than MH? IMO, the downside of using a canopy mounted MH is just to great when you consider all the other lighting options available today.

1FishTwoFish
10/14/2014, 09:34 PM
I've considered it and have tried other lighting options, but the overall results with metal halides seem to be the closest to what I would like to achieve. Not saying other lighting options are not capable, but with other variables.

SGT_York
10/15/2014, 10:06 AM
a fan on the water is always a good idea, but not a requirement since you don't have a canopy. The ambient temperature of your home will be a key factor as well.

jda
10/15/2014, 11:37 AM
How big is the system? My 250g+ systems don't even budge with multiple MH on them. Smaller will.

I do use pendants. Canopies are worse on heat.

I use Ranco controllers for temp and since they are dual stage, I do have a fan over the sump if needs be. I have it come on at 1 degree and It rarely comes on.

ca1ore
10/15/2014, 03:07 PM
Always thought fans were necessary to cool the electronics/ballast when stuffed into a sealed metal tube (aka, the fixture). As long as that stuff is remotely located, I have never felt the need for a fan.

1FishTwoFish
11/05/2014, 12:01 AM
Balast will be remotely located somewhere within the stand with a fan to cool it. The overall system will be approx. 60 gallons. A 40 gal breeder tank and the sump. I will be tying in a 30gallon frag system down the road