keeping water cool?

[69camaro540]

i have a 120g reef ready tank. i built a canopy for it and currently have 2 400 watt metal halides. i know i need to add some fans to cool the canopy, but should i add 2 or 4. i am trying to keep things cool without having to buy a chller. the setup is new so there is nothing in the tank. i am planning to have sps corals and some clams and a few fish. any suggestions on trying to keep the water a little cooler? the tank temp is 76 degrees without the halides on. after 6 hours the temp goes to 82 degrees. any suggestions? thanks jody

 

[bertoni]

82 is what I target for my tanks, so that doesn't seem too bad.

What kind of fans are you using?

 

[supertech3]

IMO your tank temp is fluctuating to much, I have canopy over my tank also and i use a chiller and mine only fluctuates 2 degrees. If you are only going to use fans you better put as many as you can and hope this works.

 

[areze]

put in a heater at 82 degrees? thats what Ive done. mine is 82 with lights on. so I put the heater at 82 so it stays the same day and night atleast.

 

[69camaro540]

so what is the most a tank should flucuate in temp? of course least would be better but what would be the max?

 

[DgenR8]

Some animals are more sensitive to temp fluctuation than others, so what you keep has a bearing on "allowable" fluctuation. I still would not want more than 2, possibly 3 degree swing over the course of a day.