Water heating with MH's

[Casey1]

I have a big heat issue. my Tank goes sky high when the MH's are on. I have two fans blowing in and even left the front open to let the heat out but it still hit in the upper 80's I even hit 90 once!!

Any suggestions? I'm only keeping the lights on for about 5-6 hours right now because it gets soooooo hot

Here's a little more info..
75g
Bullet 1 Protein skimmer with Sen 900
quiet one return
2 400W MH 10 inches away from the water
1 150 Super actintic

Like I said I'm just cycling right now so I want to get this under control before I intoduce anything. I really can't afford a chiller right now..

 

[Anonymous]

what's your room temp? do you have reg ac? do you blow air with the fans onto the water surface?can you elevate the lights?

 

[Casey1]

Thanks...

Reg Air -- 74F

no can't raise them anymore...

Air is circulating 2 seven fans one blowing in inbetween bulf and water.. I put my hand inside and I can feel it both on water surfac and by the buld. Second one blowing out...

 

[4angel]

I will assume that you took this into account already but just in case, I have my fans set in the direction that my ac is blowing out. i.e.: ac blows out to the left side of the tank, fan is pulling in air from that same side. It seems to be doing the trick. Also when it gets really hot I cut down on the MH and keep my atinics on longer.
_________________
Ferrari 340

 

[Anonymous]

how low does your temp get at nite?(i.e. lights off)have you tried a clip on fan on your sump?do you have alot of powerheads inside the tank?are your halides in an enclosed canopy,and does it have its own fans?

 

[Casey1]

Yes 4Angel the fans are working with the AC.. Good point..

the temp gets down to 80 at night. I have 3 pwr heads in the tank

No I haven't put a fan in the sump. I may try that next. Today I did the fans like I said and it's keep it down a lot. its around 81 right now. The first day I had both fans blowing onto the bulb and it didn't seem to help much. Now I have them like I said one in and one out. and it's doing alot better

 

[Nelliereefster]

I'm impressed by the wattage you're employing!!! What are you intending on growing?

I have one fan the pulls air into the hood, and one that pulls it out on the other end. In addition to that, I have a vornado fan that blows behind the tank up into the hood. I also have a standing circulating fan in the room to keep air moving around. My temp is stable at 79. 79 gallons is less of a stable mass for temp stability. If you can increase your water volume it will help.

One more trick is to have your fans on the same circuit at the light's timer, so hat hey're on whenever the lights are on.

A fan in the sump is a great idea as long as there is a way for the moisture laden warm air to escape, and fresh air to enter.

 

[brogliei]

Casey,

Plain and simple, you've got to much wattage for the size of your tank (assuming you have a 48x18x20, ~.5m^2 surface area). Sure your wattage (~ 1600 W/m^2) is really high compared to natural sun (1000W/m^2, iirc), and in a small tank that can't disipate the heat fast enough it is overkill. I would say change to 250s (~1000W/m^2) or 175s and that should solve your problem. I run four VHOs (440W) for my 75 and that seems fine. The temps do get to 85-86 during the heat of the day, but that is nothing to worry about. Besides, I think most of my heat in the tank is generated from one of my return pumps. My lights only increase the water temp around 2-3deg. We can talk more about it at Jason's next Wed.

peace
Ian

 

[Anonymous]

You could also raise the lights to 14-16 inches. As well as switch to 250s.

 

[danmhippo]

Worse comes to worst, you will probably have to get a chiller. You will feel safer with it connected in the long run. Get at least 1/2 horse power. Comparing how much you've already invested in to your tank, a chiller acts as the insurance premium.

Try also the reverse lighting, meaning lights off during the hottest hour (day time), and lights on at night.

 

[elpescado]

I agree with brogliei, in that you have way to much light for the size of the tank. With that much wattage the heat put out is tremendous. Granted a chiller would keep it cool, but it will have to work overtime, ending up costing you a lot of money to run. I suggest dropping down to two 175 watt halides and two 110watt actinic VHOs (or two 96watt actinic blue PCs.). Put the 400watters over something like a 120gal, 110show, 220gal or something else at least 24 inches tall or taller.
If the hood is ventilated well enough the water shouldn't heat up to much (as long as the house temp doesn't get to high). Run the Actinic blues for about 10 to 12 hours and the Halides for 6 to 8 hours. I have my fans turn on a few minutes before my halides and shut them off about a half hour after my halides shut off.

 

[flameangel1]

Note,,
The Quiet One pump puts out a lot of heat also.
Have seen it raise the temp 4 degrees in a 75 gallon tank.

 

[Casey1]

Thanks gusy for all your suggestions...As far as the over wattage goes. I was told that I needed it if I wanted to keep sps and clams...

 

[flameangel1]

Note,,
The Quiet One pump puts out a lot of heat also.
Have seen it raise the temp 4 degrees in a 75 gallon tank.

 

[brogliei]

Casey,
I have sps and they do great. I have no clams, however I don't think clams would have a problem with my lighting at all. Remember Jason has two 400W MHs for his 150gal and his tank does great.

good luck
peace
Ian