MH and Heat

recall · 09-21-2002, 02:26 AM

Ok so i was all set to add two MH to my 60 gallon to accompoany the PC's when my LFS tells me I can't do it because it will drastically raise my temps and a chiller will be mandatory. I personally think he is talking out of his arse because he is well aware i will not be purchasing these lights from his store. I currently push about 200cfm through my canopy so i should have airflow licked. I really don't think they will heat the tank past acceptable temps but wanted to run it by all of you first. Please keep in mind I live in Santa Barbara where the temp is 70 +-5 degrees all year. Also The MH's will only be about 2-3" from the surface so this may cause a problem. What does everyone think?? Can I order my MH's?? (either 175 or 250 W)

DeepSix · 09-21-2002, 04:35 AM

i think 2~3" is a bit too close for metal halides, especially if they aren't protected from the occassional splash by a glass sheild. i believe 8-10" spacing for up to 175w, and 12" or more for larger wattages is a good rule of thumb. and yes, the potential to over-heat your tank is possible.

Rick O · 09-21-2002, 05:10 AM

I agree that 2-3 inches may be a bit risky. A splash of water on a hot bulb will crack it.

As for heat it depends on how ventilated your canopy is. Is it possible to have one fan on each end? One blowing in and one blowing out. You can also position a fan to blow over the surface of the water in your sump. This will help cool the water. I believe the fact that you live in a moderate climate will have a huge impact on heat buildup.

Reedman · 09-21-2002, 09:54 AM

I agree with the others on the height off the water. I have 2 250W MH on a 75 gallon and they are about 11" off the water and I still see water spots on them from me working in the tank.

As for temperature, I have a cheap clip on fan ($8 at Fred Meyer) at one end of the canopy blowing across the length with the other end acting as an exhaust. Temp rarely goes above 81 degrees. I plan to upgrade to a better fan setup later, but you get the idea...a chiller should not be a required piece of equipment...recommended maybe...but not required.

My 2 cents worth.