Hood lighting - computer fans

Husky_1 · 09/10/2007, 12:08 PM

I am building my 92g hood and was wondering how many CPU fans I should use. In the hood I will be using 1x250 MH, 2x24 T5's and 2x39 T5's. How many fans do you think I should use. Will 2 do the trick or should I do more? I will also have a few vents at the top to help air escape as well. For assumption purposes, lets assume that I am using 80mm fans with about 40 CFM (Zalman 92mm).

Also, any tips to mounting these, or what color wires to hook up to the power sources would be of much help.

I do plan on using the dust covers, and a adjustable DC power supply.

Thanks,
Dale

Husky_1 · 09/12/2007, 07:06 AM

Any one?

AZDesertRat · 09/12/2007, 08:45 AM

I only use 2 on my 100G with 2x25ow MH and 2x140w VHO. One in each end blowing in with exit holes on the very top directly over my reflectors. Fans are 53CFM Vantec Stealths at 28 dBa and powered by Harbor Freight DC variable voltage power supplies to vary fan speed with the seasons and heat load. Been working good for almost 4 years now.

Husky_1 · 09/12/2007, 12:41 PM

AZ, thanks for the suggestions. I like the idea of changing the fan speeds

AZDesertRat · 09/12/2007, 01:09 PM

Variable voltage DC power supplies can be found at Wal Mart, Radio Shack, Frys Electronics, Newegg and a number of other places. Some like mine are only $5 ea. Good quiet 120mm (4") Vantec Stealth fans can be found at newegg.com for about $12 each.

MSU Fan · 09/12/2007, 01:23 PM

I think that I keep getting ripped off then, since the Radio Shack near me sells them for $19 each for the variable voltage AC to DC adapter!

Husky_1 · 09/12/2007, 01:50 PM

Thanks again AZ, I just ordered to of the zalman z3's but I can always return. I will definitely keep those in mind though. As for the variable DC, I have seen them around, they should not be an issue to find. I happen to have 2 HF's within a decent range so I may swing by.

MSU, Anything at RS is a ripoff...

Jefe12234 · 09/12/2007, 04:08 PM

I used two 120mm fans on my newest tank with one 250w MH. The temp never goes very far above ambient, so I think the fans are doing a good job. I also mounted the fans on top of the hood blowing up. There are gaps at the bottom of the hood for air to enter, so the air is constantly moving up and out of the hood. I think this helps a lot to remove heat since hot air naturally rises.

oct2274 · 09/12/2007, 04:16 PM

i also use two 120mm fans, one intake and one exhaust on the opposite end of the canopy. here are the ones i use:
http://www.antec.com/us/productDetails.php?ProdID=75121

they are very quiet, even on high you can barely hear them unless you are right next to them. They make a huge difference and I do not need to use a chiller even when my temp in my house is 79-80. They are still able to keep my aquarium temp at 81.3 or lower. I use my aquacontroller to kick them on when tank temp hits 81.3 and they turn back off again when it gets to 81.1.

AZDesertRat · 09/12/2007, 04:50 PM

The problem with one in and one out is you only get the CFM volume of one fan. Why have two when one would do the same amount of work. You can stack 100 fans in a row but the last one is only going to move the same air the first one fed to it. Tow in is much more effiecient with exit holes as high up as possible and at least equal to if not bigger than the opening size as the fans so you do not create head pressure.

With fans sucking air out you also drastically shorten the fan life due to drawing moist hot air through it. Pushing cooler dry air into the canopy at a low spot will make them last much longer.

I think I have tried every combination known to man in the last 17 years including AC fans, different sizes, speeds, directions etc. and finally settled on the way I do it now.

oct2274 · 09/12/2007, 05:25 PM

i'm used to having push and pull because having all push in a an enclosed canopy or computer case for that matter doesn't work for crap. In those types of applications it is actually better to pull then push and have atleast as much pull as push if not more pull, but since my canopy is open on the top it definitely would make more sense to have mine both pointing in! The airflow will easily vent off through all the openings. Thanks for making me think

I'll switch the pull fan around tonight!

AZDesertRat · 09/12/2007, 05:31 PM

My canopy is totally enclosed on all sides, no openings in back or anywhere except for the fans on the ends and exit holes on top. Both fans blowing in is still the best option I have tried and as I say I have tried them all. As long as you have sufficient openings for heat to rise and escape its very efficient. Computer cases don't have openings on top so it would not work for them. I went without a chiller for 15 years with just this configuration. Only added the chiler 2 years ago because I got such a good deal on it used.

Husky_1 · 09/13/2007, 07:27 AM

thanks again to all, it sounds like 2 fans will do the job. I think I will follow AZ's suggestion of 2 in, and vented out. I did read this in the past, and makes sense.

Oct, I do know what you mean with computers, normally you would run a push and a pull, but I think the difference in thinking is that the tank will have the evacuation vents...BTW, I love that flasher in your Avatar. I used to have one but he went missing. One day when I was moving my tank I found him behind it, he was a jumper....

BTW, do you guys use filters for your fans? Does this really make much of a difference in the quality of air coming into the hood?

AZDesertRat · 09/13/2007, 08:25 AM

I tried filters andall they did was restrict flow. If light escaping is a concern, you can find lots of grilles to put over them. Rockler woodworking supply also has some really nice unfinished wooden louvers that can be stained to match.

Husky_1 · 09/13/2007, 08:39 AM

Hey AZ, I will keep the Rockler in mind, I may use them for the top, but the sides are not a concern since this is a corner tank...

Husky_1 · 09/13/2007, 08:41 AM

I should have mentioned that light emitting was not my concern for the sides...

flapjack1439 · 09/13/2007, 09:16 AM

This is the best place I found for fans. Good prices and wide variety. You can't hear the ones I bought and they move a lot of air

http://www.coolerguys.com/.

09/10/2007, 12:08 PM	#1
Husky_1 Premium Member Join Date: Jun 2006 Location: South FL Posts: 1,541	Hood lighting - computer fans I am building my 92g hood and was wondering how many CPU fans I should use. In the hood I will be using 1x250 MH, 2x24 T5's and 2x39 T5's. How many fans do you think I should use. Will 2 do the trick or should I do more? I will also have a few vents at the top to help air escape as well. For assumption purposes, lets assume that I am using 80mm fans with about 40 CFM (Zalman 92mm). Also, any tips to mounting these, or what color wires to hook up to the power sources would be of much help. I do plan on using the dust covers, and a adjustable DC power supply. Thanks, Dale

09/12/2007, 07:06 AM	#2
Husky_1 Premium Member Join Date: Jun 2006 Location: South FL Posts: 1,541	Any one? __________________ Out of the hobby, but thinking of rejoining Current Tank Info: 92 Reef, 10 Reef

09/12/2007, 12:41 PM	#4
Husky_1 Premium Member Join Date: Jun 2006 Location: South FL Posts: 1,541	AZ, thanks for the suggestions. I like the idea of changing the fan speeds __________________ Out of the hobby, but thinking of rejoining Current Tank Info: 92 Reef, 10 Reef

09/12/2007, 01:23 PM	#6
MSU Fan Registered Member Join Date: Mar 2007 Location: Russellville, TN Posts: 1,645	I think that I keep getting ripped off then, since the Radio Shack near me sells them for $19 each for the variable voltage AC to DC adapter! __________________ Craig & Holly 1-29g FW 5-cats, 1-dog (Shepherd Mix) Current Tank Info: To be set up 44g corner pentagon

09/12/2007, 04:08 PM	#8
Jefe12234 Registered Member Join Date: Apr 2001 Location: MN Posts: 885	I used two 120mm fans on my newest tank with one 250w MH. The temp never goes very far above ambient, so I think the fans are doing a good job. I also mounted the fans on top of the hood blowing up. There are gaps at the bottom of the hood for air to enter, so the air is constantly moving up and out of the hood. I think this helps a lot to remove heat since hot air naturally rises. __________________ Serenity now!!!

09/12/2007, 08:45 AM	#3
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	I only use 2 on my 100G with 2x25ow MH and 2x140w VHO. One in each end blowing in with exit holes on the very top directly over my reflectors. Fans are 53CFM Vantec Stealths at 28 dBa and powered by Harbor Freight DC variable voltage power supplies to vary fan speed with the seasons and heat load. Been working good for almost 4 years now.

09/12/2007, 01:09 PM	#5
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	Variable voltage DC power supplies can be found at Wal Mart, Radio Shack, Frys Electronics, Newegg and a number of other places. Some like mine are only $5 ea. Good quiet 120mm (4") Vantec Stealth fans can be found at newegg.com for about $12 each.

09/12/2007, 01:50 PM	#7
Husky_1 Premium Member Join Date: Jun 2006 Location: South FL Posts: 1,541	Thanks again AZ, I just ordered to of the zalman z3's but I can always return. I will definitely keep those in mind though. As for the variable DC, I have seen them around, they should not be an issue to find. I happen to have 2 HF's within a decent range so I may swing by. MSU, Anything at RS is a ripoff...

09/12/2007, 04:16 PM	#9
oct2274 Registered Member Join Date: Feb 2006 Location: Plano, TX Posts: 2,347	i also use two 120mm fans, one intake and one exhaust on the opposite end of the canopy. here are the ones i use: http://www.antec.com/us/productDetails.php?ProdID=75121 they are very quiet, even on high you can barely hear them unless you are right next to them. They make a huge difference and I do not need to use a chiller even when my temp in my house is 79-80. They are still able to keep my aquarium temp at 81.3 or lower. I use my aquacontroller to kick them on when tank temp hits 81.3 and they turn back off again when it gets to 81.1.

09/12/2007, 04:50 PM	#10
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	The problem with one in and one out is you only get the CFM volume of one fan. Why have two when one would do the same amount of work. You can stack 100 fans in a row but the last one is only going to move the same air the first one fed to it. Tow in is much more effiecient with exit holes as high up as possible and at least equal to if not bigger than the opening size as the fans so you do not create head pressure. With fans sucking air out you also drastically shorten the fan life due to drawing moist hot air through it. Pushing cooler dry air into the canopy at a low spot will make them last much longer. I think I have tried every combination known to man in the last 17 years including AC fans, different sizes, speeds, directions etc. and finally settled on the way I do it now.

09/12/2007, 05:25 PM	#11
oct2274 Registered Member Join Date: Feb 2006 Location: Plano, TX Posts: 2,347	i'm used to having push and pull because having all push in a an enclosed canopy or computer case for that matter doesn't work for crap. In those types of applications it is actually better to pull then push and have atleast as much pull as push if not more pull, but since my canopy is open on the top it definitely would make more sense to have mine both pointing in! The airflow will easily vent off through all the openings. Thanks for making me think I'll switch the pull fan around tonight!

09/12/2007, 05:31 PM	#12
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	My canopy is totally enclosed on all sides, no openings in back or anywhere except for the fans on the ends and exit holes on top. Both fans blowing in is still the best option I have tried and as I say I have tried them all. As long as you have sufficient openings for heat to rise and escape its very efficient. Computer cases don't have openings on top so it would not work for them. I went without a chiller for 15 years with just this configuration. Only added the chiler 2 years ago because I got such a good deal on it used.

09/13/2007, 07:27 AM	#13
Husky_1 Premium Member Join Date: Jun 2006 Location: South FL Posts: 1,541	thanks again to all, it sounds like 2 fans will do the job. I think I will follow AZ's suggestion of 2 in, and vented out. I did read this in the past, and makes sense. Oct, I do know what you mean with computers, normally you would run a push and a pull, but I think the difference in thinking is that the tank will have the evacuation vents...BTW, I love that flasher in your Avatar. I used to have one but he went missing. One day when I was moving my tank I found him behind it, he was a jumper.... BTW, do you guys use filters for your fans? Does this really make much of a difference in the quality of air coming into the hood? __________________ Out of the hobby, but thinking of rejoining Current Tank Info: 92 Reef, 10 Reef

09/13/2007, 08:25 AM	#14
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	I tried filters andall they did was restrict flow. If light escaping is a concern, you can find lots of grilles to put over them. Rockler woodworking supply also has some really nice unfinished wooden louvers that can be stained to match.

09/13/2007, 08:39 AM	#15
Husky_1 Premium Member Join Date: Jun 2006 Location: South FL Posts: 1,541	Hey AZ, I will keep the Rockler in mind, I may use them for the top, but the sides are not a concern since this is a corner tank... __________________ Out of the hobby, but thinking of rejoining Current Tank Info: 92 Reef, 10 Reef

09/13/2007, 08:41 AM	#16
Husky_1 Premium Member Join Date: Jun 2006 Location: South FL Posts: 1,541	I should have mentioned that light emitting was not my concern for the sides... __________________ Out of the hobby, but thinking of rejoining Current Tank Info: 92 Reef, 10 Reef

09/13/2007, 09:16 AM	#17
flapjack1439 Registered Member Join Date: Jan 2005 Posts: 1,056	This is the best place I found for fans. Good prices and wide variety. You can't hear the ones I bought and they move a lot of air http://www.coolerguys.com/. __________________ Convicted? Nooo..........never "convicted".