Water temp won't go down -- Question

[wintrmte]

I've turned our heater down to 70 deg. and the water temp won't seem to decline. I'm not sure it's the lighting, as we've got some pretty decent fans moving the air out of the hood.
Even during the night, with the lights off for 12 hours, the temp still stays at about 78 deg.
My thought here is that maybe the powerheads are generating heat, which is keeping the water temp from declining?
Are there any good powerheads that don't output a lot of heat?
Thanks.

 

[cprdnick]

Post your specs in detail about all of your equipment. Pumps, PH's, lighting, skimmer, heater brand and model. how far off of the water are your lights.
Where is the heater vent in that room? I could have not heater and no lights in my tank, and my temp would still stay around 76-80 with the central heat in my house blowing. I didn't plan it, but my heater vent is pointing directly at my aquarium.
As far as low heat PH's I'm not real sure.

 

[exotickeeper]

Perhaps it's not your powerheads, what is room temperature?
One other possiblity is that heaters go crazy after awhile. It has happened to me many times, I turn the heater to the lowest, and it's like 83 degrees. That's when you need to replace heater, so check all the obvious first. I doubt just your powerhead alone will generate all that heat.

 

[bang guy]

I agree with Nolo, if it's below 85 I'd suggest adjusting your heaters so the temp doesn't fall more than 2 or 3 degrees and just run your tank warmer.

 

[wintrmte]

Thanks for the replies all! The normal room temperature is about 73.
As for the light placement, I'd say it's about 4 to 5 inches above the glass. Maybe a bit higher than that (PC Lighting, btw) with two 120mm fans at each end pulling air.
I went ahead and replaced all the power heads in the tank with Maxi-jets. I figured the ones I had (power sweeps) quit sweeping and worked as standard heads anyway, and I've read a lot of good things about the maxi's.
I will say though, after removing the one JBJ powerhead I had, the tank temp shows it's at a nice 76 right now, which its never read. Hopefully I've got this problem solved.
Thanks again all

 

[shine~on]

Yea, the only Maxi Jet PH to be concerned about putting a lot of heat off is the 1200, its like 2.5 times watts more than the lower model (900).

 

[skirrby]

you said the lights are above the glass.. do you have a glass top on the tank. ive heard that glass tops can hold heat in. might help to remove the top. but your evaporation might be more

 

[bang guy]

76? brrrrr

 

[reefnut]

What temp are you shooting for? IMO 76 is a little on the cool side.

 

[asbury030]

and also is it in direct sunlight i had that problem.