Metal Halide lights heating my aquarium

[charvatg]

Hi Everyone,

I have a 29 gal reef tank that has been running since October. I recently added a 175w metal halide and it is causing the tank to heat up alot when its on (upwards of 85 deg or more). I run the AC in my apt, but that doesn't cool it enough. The MH bulb is about 6 to 6.5 inches above the water line, with a peice of plate glass protecting it from splash (which is about 5 inches above the water line).

I'm also running one small fan, sort of blowing on the bulb. Should i add more? Is the heating caused by the heat around the bulb or is this heating caused by the light intensity itself?

I'm new to MH lighting. Any suggestions would be helpful.. Thanks again for your help! Greg

 

[bdelaney]

Are you running with a canopy or an open top? With a sump or without?

I have a 29g with a 175W metal halide pendant and a sump. The temperature never seems to go above 78 degrees. The open top seems to really help.

If you're using a canopy, you are probably going to have to increase the airflow. MH bulbs throw off a lot of heat, and you need to dissapate that somehow. A little more distance between the bulb and the water might help. If you have a sump, a fan across the surface of the water might help as well. Some kind of auto top-off might be needed since your evap rate will increase.

 

[charvatg]

Yes, i do have a canopy that i constructed out of wood. But, there is no glass or anything directly above the water. I have lots of little fans lying around here that i could use to cool it, i will try that right away.

Unfortunately i don't have a sump. And i'm a little worried about this evaporation problem. I travel alot for my job, 2 or 3 days at a time.

So what is this auto top-off system you are talking about? I've never heard of one, but i would like to get it!

Also, how long should i run the MH bulb for each day? (ive heard of people only running it for 4 to 6 hrs per day)

Thanks for the info!
Greg

 

[Emperator]

instead of blowing the fan at the bulb, blow it directly at the water surface. also running your lights later in the day (when it is cooler) will help a lot. i plan on running my halides from 6pm till 2am to battle the heat.

 

[Robin Goodfellow]

hi.
I run my light from 6pm to 6am. It is like 100 F during the day, and 60 during the night in past few days here in the South Cal., so this really helps.

You may want to check out the library section of RDO as well as searching/browsing around to get more familiar with the hardware that reefers use.

 

[charvatg]

These are all great suggestions. Tonight i will offest the time that the MH lamp is on, and this weekend i will install some fans, everywhere...

Thanks again for all of your help, glad this is not an uncommon issue to deal with in the MH realm.

Greg

 

[panmanmatt]

i am currently running a 250 watt mh on a 60 hex in a stainless steel hood with no heating problems. i have a three speed automatic fan purchased from drs foster and smith. during the week the light is on from 3pm til 9pm and from 10am til 9pm on weekends. my bulb is only four inches from the water with glass in between for splash protection. as long as the fan stays on the tank stays at 82 degrees no matter what the temp is in the house.

 

[MarkO1]

I run a fan over my main tank and the evaporational cooling accounts for about a 5 or 6º difference! Of course when it runs, I lose about 1/2 to 2/3 a gallon per day of water so auto top off is necessary. For me it was easy, I converted an old 7.5 gal. glass jug beer making kit into a gravity fed auto top off. Of course for me it's a bit easier since I have a sump and the auto top off works off the water level in the sum, so I don't need that jug way up high. There is a GARF website (http://www.garf.org/) out there that tells you how to set up an auto top off system. It's really simple to do and costs only a few bucks ($20 tops) and never needs power.
Good luck and be cool
_________________
Eye / Vision Forum

 

[Apophis924]

have you tried having the fan point directly at the surface of the water. I think you will get better results having the fan aimed at the surface of the water rather than cooling the bulb. I run a 20H with 250 watt 10k metal halide pendant about 6 inches above the water surface. I have a six inch desk fan blowing on the surface and my temp hovers around 78 to 79 degrees when the lights are on. Granted i have a LOT of evaproation but with sps i need that much evap while dosing kalk to keep up with the ca++ demands of the system.