[dclaghorn2]

I have a 48" canopy housing two T5s and two MHs (10,000K - 250W). This is really raising my water temp (like 86-90F! and, I keep my house at 78 during the day and 75 at night.) (I'm only cycling tank now, so nothing in there 'cept live rock, sand, and - today - some algae). I want (make that NEED) to ventilate the canopy. My LFS said I could try computer fans. So, off to Fry's I went. Got to two 92mm 58 cfm fans, one for each side. I was wondering would it be best to blow cool air from the outside into the canopy forcing the hot air out the back, blowing cool air from the outside in one end and exhausting out the opposite side - which would also draw cool air in from the back, OR, exhaust both fans to the outside drawing in cooler air from the back of the canopy...

Thanks,
Dave

[CyberJester]

I would say one in one out. This should create the air movement need to remove the hot air from the heat space.

[dclaghorn2]

Also, does 58 CFM/fan seem like enough? It is 92mm (3-9/16") and the canopy is about 8" high. So, I would worry that if I went to a 70-80 cfm, 102mm fan, I could be compromising the structural integrity of the wood. I figured I could always add additional fan in series if needed...
Thanks,
Dave

[jvharding]

I think that this will help cool your system but not enough to eliminate having to install a chiller! What Equipment are you running other than 2 250W MH?

[NATIVEVAMAN]

I would think that if you put enough fans in the canopy to keep the tank cool you are going to need a really good auto top off unit.

[dclaghorn2]

hmmmm... I'm already adding about 1 gal/day.
Aside from the 2 MHs, I have 2 T5s, 2 lunar LEDs for night time, 2 powerheads at 1500 gph, and the All Flo Freedom Filter with a 660 gph pump in it. Yesterday, I just left the top of the canopy open and the temp never exceeded 84.

Thanks,
Dave

[NATIVEVAMAN]

Well one trick might be to increase your water volume.I didnt see that you mentioned a sump,do you have one?

[dclaghorn2]

No, I sure don't. Just the hang IN the tank variety.

[NATIVEVAMAN]

It looks like you will need tout at least two fans in the canopy or raise the canopy to ge the lights further off the water or get a chiller.I think the combo of the first two options will be the cheapest.

[NATIVEVAMAN]

OH,or you could get rid of those mh lights and go all the way with t5,which may be cheaper than a chiller.

[ksreefbuilder]

Originally Posted by dclaghorn2

hmmmm... I'm already adding about 1 gal/day.
Aside from the 2 MHs, I have 2 T5s, 2 lunar LEDs for night time, 2 powerheads at 1500 gph, and the All Flo Freedom Filter with a 660 gph pump in it. Yesterday, I just left the top of the canopy open and the temp never exceeded 84.

Thanks,
Dave

I have the same light setup as you, but have a larger water pump and a 30 gal fug. I was told just to put some thick screen wire similar to what is on your windows on the bottom on the canopy where it sets on the tank. I thought it was crazy, but after talking to a few people found out it was worth a try. The screen absorbs a lot of the heat before it can hit the water and then the fans cool it, and still lets all the light through like it is not there. My tanks sets at a steady 83 with no problems. It was a cheap solution for me.

[dclaghorn2]

They all said it couldn't be done. Well, I am here to testify, that I placed two 90mm computer fans in my hood and drilled one 3" hole in the top. I sent the airflow in one side and exit the opposite end. Before the fans, my temps ranged from 80 in the a.m. before lights coming on to anywhere between 86-89F at the end of the day when the MHs finally kicked off. House stays at 77-78F.

Now, since the fans are installed, the tank has stays between 76-80F. Everyone insisted I HAD TO HAVE a chiller... Well, I just saved $700 by forking out $50 at Fry's Electronics... Water is now clearer, fish seem pretty happy, my mushroom has really opened up.

Dave

[pyromaniac398]

Congrats on the fans working out

[aquasalt]

Dave, any chance you could post a picture of your modification and a link to the fans you used?

[jsgates]

I am currently doing the same type thing. How did you wire your fans to power them? I work in IT and install these things all the time in PCs, but I have to convert AC to DC somehow. Fans I have have yellow wire 5v, red wire 12v, & black wire ground. I'm looking for a cheap way to convert the power. Any suggestions? thanks.

[ksreefbuilder]

I just bought some 12 volt DC fans from radio shack for $15 each and bought a AC to DC power supply as well and wired them in parallel and it works great.

[jsgates]

Yeah. I had to make it hard on myself by getting variable speed fans. not sure what to do with the 5 volt yellow wire.

[Lazy Iguana]

Hot air rises. So I would cut vents in the back of the hood and then put the fans in so they blow air out from the top.

And should one of the fans quit, you still have passive ventilation.

The MH lights create more heat, so the fans should be located near them.

I would not cut intake vents too close to the MH lights, too much cold air blowing on the hot lights *COULD* cause uneven heating which could then cause the light to explode. Maybe.

Design the system so the fans can run independently of the lights. You will want to keep the fans going for 10 or so minutes after the lights switch off.

[dclaghorn2]

I used a computer power supply and computer fans. Everything just plugged in fine to each other. Now in the winter time, I have my fans on the same timer as my MHs. Keeping things at a cozy 78F. Will post pics soon.

Dave

[Tkouz]

WOW, seems like the computer fan is the popular solution..... has anyone thought of using cool tubes?? they are the best thing.... you can install 1000W halides in there if you want.. I use it on my tank, I dont use any fans to keep it cool, but thats because I only have it hooked up to a 250W.. waiting for myother digital balast and bulb to arrive...then I will probably need a fan..

check out the thread I posted " the perfect lighting solution"..


"DIY" till I die!!!

[spamreefnew]

just one word of caution,,,buy extra fans mine get very dirty and die all the time