Reducing heat from MH

[Alysiak00]

Hello, was wondering if anyone had any tips on reducing the heat added to an aquarium from the MH. I have a 45 gal which i just hung a 2x150w mh sunpod setup above it. Its hung about 12" above but still produces tons of heat. i ended up putting a clip-on fan blowing across the water and this helped a little.

my main question/problem is that when the lights come on (4pm-10pm) the temp is around 78.3 but by the time they turn off it climbs up to 82.0

i'm pretty sure that this will be bad on the corals. any ideas

 

[mike_cmu04]

82 isnt bad. since you are already using fans the only thing really left to do is try frozen bottles of water and if that dosent work you need a chiller.

 

[RVANANO]

I have the same issue. My tank and it's inhabitants have been fine with that swing. I have my Apex set to cut the MH's when the temp gets above 82.5 IIRC.

I plan on mounting 3 5" fans on each side of my center brace facing towards the water surface similar to your setup. I imagine the temp will stay b/t 77.2-80 with the extra fans.

Nothing else you can really do short of a chiller. I will do whatever I have to in order not to run a chiller though.

 

[Uncle Salty 05]

Got any pics?
Are they in an enclosure or just pendants?
If you are handy with wood I would suggest building an enclosure so you can direct the heat where you want it to go.
Once in an enclosure you have very few cubic feet of air to move.

 

[RVANANO]

IMO enclosing the lights will only make the heat issue worse.

 

[Uncle Salty 05]

I have 3 x 250 watt MH and 4 x 96 watt PC in an enclosure that rests right on top of my tank (see avatar). The inside of this enclosure is appoximately 6 cubic feet. I have two 3" fans blowing in (one on each end) and a 4-3/4"
fan like this on top.
http://www.fosterandsmithaquatics.com/product/prod_display.cfm?pcatid=3868

Do the math. 102 divided by 6 = 17. The air inside the enclosure is removed 17 times per minute. It is like a wind tunnel inside. Heat doesn't have time to build up.

 

[frankpayne32]

The evaporative cooling power of fans is really pretty remarkable. Add more fans or more powerful fans and I bet you will see better temperature stability.

 

[Alysiak00]

the setup is just a 36" sunpod being hung above it by a tube stand. the bottom of the sunpod is 12" off the water line and like i said i have one fan on it. i'm thinking of maybe getting another fan for the other side and seeing if it helps. what scares me is the chance of coming home to a cooked tank!!!!

 

[chimmike]

expect your evaporation to increase and you'll need to add more fresh RO to make up for it.

 

[Alysiak00]

thats okay i have a 6 gallon ato reservoir that i check regularly

 

[frankpayne32]

Also, to increase the efficacy of your fans point them directly at the water's surface (not just blowing over the top). Surface agitation via pumps/powerheads will also help.

 

[strike2867]

Bigger fans that agitate the surface more. What is the temperature in the room like? My tank usually runs 3-5 degrees warmer(2 250 mh over a 90). Could you run the MHs at a different time, when the room temperature is colder?

 

[sirreal63]

That temp swing is perfectly fine, and normal. The fan helps a lot.

 

[t4zalews]

my tank operates at the exact same temperature without any problems...if the temp goes above 82..my APEX shuts off the halides. If the temperature remains higher, I run my built in fan in my canopy and if I need more I clip a fan on and everything stays fine. You could even run the fan at night to make your tank drop more in temperature before the lights come on. My tank easily runs at 76 during the night and as high as 82 during the day without any problems.

 

[Alysiak00]

Whew that makes me feel better. It stinks because is relatively small so the mh affects it more.

 

[ddmiller38]

I added a 80mm computer fan at the ends of the unit.. Radio Shack has them for 9.95 and they fit great the only thing you have to do is drill the 4 holes.. BTW make sure the fans are running on the top of the unit..

 

[Alysiak00]

the fans on the top are definitely working i think my room is just a little cramped lol. i came home today and to my surprise the tank was only at 79 with just the fans on the sunpod and the clip on

 

[frankpayne32]

Chiller would solve the problem

Chillers are an unnecessary waste of money and electricity in most situations. Most temperature stability issues can be solved using the advice in the above posts. No offense meant BTW. :beer:

 

[Korrine]

IMO enclosing the lights will only make the heat issue worse.

actually I think it helps. Have one fan blowing into the hood and another blowing out. Instant heat loss!! I've seen this application in action too and will utilize it on my tank since I'll have from 500 - 650 MH watts over a 75g tank.

 

[Alysiak00]

i would do that but i would need to make a canopy