Halide Heat Management - Opinions Wanted
 

So I recently installed a dual 250W DE halide retro into my hood (standard 90 gallon). I have my temperature set at 78, holding steady at 77.6 - 78.4 with fuge lamp and T5 actinics on, when the halides come on the temperature reaches up to about 83.5 when the ambient temperature of the room is about 72, when it was about 78 the other day I spiked to 85.3 before turning the lights off before a full photoperiod was complete. (tank is new and cycling, so there are no inhabitants at this point.)

Having said all that Im trying to decide on the best way to cool the system. As of yet I havent added any fans, and of course I plan too, but do you guys/gals think that will be sufficient to control the problem, control being defined as limiting increase to less than or equal to 82? Do you think this situation will require a chiller?

No doubt this problem is widespread and Id like to find out how others are handling the issue.

Fans should be enough. I run 2x250 on my 75 and believe it or not my tank actually runs warmer at night with no fans and my 25x3 cheato light on. I run 2 4" fans at about 50% during the time the Mh are on.

I agree with barjam - fans will help a ton. I have two 250's and two VHO's over my 65. The heater keeps it 77+ at night. During the day, with the house at 72, the tank never gets above 78.5. I have one 3" computer fan running 24/7 in the canopy. Another canopy mounted computer fan and a 6" desk fan pointed at the sump are on the same timer as one of my halides. The canopy fans push roughly 10x the canopy volume every minute. Mine is set up so all the escaping air is forced out through or next to the halide reflectors. I like this better than an open backed canopy.

Yes, fans first, definitely. Some other things to think about:

- Are your bulbs too close to the water?
- Is the light hitting anything other than the water (and thus heating it up unnecessarily)?
- When you add fans pay attention to where the air is being brought in and forced out, as miwoodar said.

Dan

I have an open backed canopy already. Is there a good way to force air through a enclosed DE halide reflector? I have circular holes cut in the end of the canopy where I can mount fans but they would not be preferentially forcing air through the reflectors.

I think I will buy like a desk fan for the sump or maybe build an acrylic brace to hold teo 120 mm AC computer fans.

You should not force air through a DE reflector, they are made to run to a certain spec heat wise. Or at least that is what I have read.

For what it is worth (someone in the thread brought it up) I run my lights about 5 inches off the water with no heat issues.

My lights are probably about 10 (maybe even 12) inches off the water, so I dont think I can improve the issue any further by changing the reflector height.

Doc, this is common with a lot of halide users. Long story short go with the fans :)