reversing fans in 12 gallon nano jbj dx

evad1 · 09/05/2006, 09:57 PM

i heard if you reverse fans in a dx it will run cooler temps
does this work?
thanks dave

sir_dudeguy · 09/05/2006, 11:29 PM

um...which way do they normally point? lol. Do they point out normally? (like an exhaust only fan?)

Mark426 · 09/06/2006, 06:23 AM

yup, works. Have them both blowing inward.

sir_dudeguy · 09/06/2006, 07:33 AM

so they normall point out? If so, switch them around...at least one (if theres more than one?). That will get air in there to cool the water off a little.

schnell76 · 09/06/2006, 01:19 PM

Pointing mine to blow inward, the reverse from stock, helped lower my temp about one degree. I do notice though after doing it that the fans are pretty loud when they kick on. After a minute they quiet down once they get up to speed. It seems like it makes the fans work harder to force the air into the small area. Might be replacing the fans sooner this way, but hey they are cheap.

sir_dudeguy · 09/06/2006, 02:54 PM

thats why if theres more than one fan i would only point one in...that way its not trying to force air into a small space thats already got air. But i dont know if they've got 2 fans

manse · 09/06/2006, 03:12 PM

There are 2 fans in the 12DX.

Jim Cannon · 09/06/2006, 05:18 PM

What if you had one out and one in? Just curious.

I think the idea of the fans is to exhaust the heat from the lights out of the tank and away from the water.

So if you change them to blow IN, wouldn't that blow the hot air over the water? Seems backward to me.

You put one IN to pull cool air in, thus cooling the lights. The OUT one would exhaust the air heated by the tubes.

Seems more logical to me. IMHO.

Mark426 · 09/06/2006, 07:00 PM

Your right Jim...point both in.....this has been tested by nanocustoms and many people over on another nano forum works best as you have already seen. One in and one out has been tried too....the problem is since the fans are so close together the air never reaches the lights your trying to cool. The air just kinds crosses over form one fan to the other.

sir_dudeguy obviously doesnâ€™t have a nanocube and really speaks without any knowledge on this subject.

nmprisons · 09/06/2006, 07:13 PM

this also significantly increases evaporation so if you don't have an auto-topoff, make sure you monitor closely.

Mark426 · 09/06/2006, 08:14 PM

Gezzzzzzzzz.... you guys. It wont increase the evaporation at all.
Look, the fans are SEALED inside the splash shield. The shield even has a rubber gasket. The fans and the airflow they generate are COMPLETLY isolated from the water in a near airtight chamber on the 12 gallon JBJ Nanocube. I am no expert by any means, but if you dont know what your talking about ...dont add to the confusion please. I am giving up on this forum...too much misinformation time and time again.

For good info on nanoreefs ...try...

http://www.nano-reef.com

sir_dudeguy · 09/06/2006, 08:24 PM

Quote:

What if you had one out and one in? Just curious.

I think the idea of the fans is to exhaust the heat from the lights out of the tank and away from the water.

So if you change them to blow IN, wouldn't that blow the hot air over the water? Seems backward to me.

You put one IN to pull cool air in, thus cooling the lights. The OUT one would exhaust the air heated by the tubes.

Seems more logical to me. IMHO

ya thats what i mean.

And no, i dont have a jbj nano cube, but to say that i "speak w/out knowledge on the subject"....idk..I see them pretty often as pretty much all the local people that i talk to have them, and i've looked at them very close because i myself have considered buying one.

Nano's arent any dif. than other tanks imo, other than size. The hood and everything is about it.

If you blow air across the water, you're going to cause it to evaporate at a faster rate, which is very usefull for cooling. Its the same thing as when you sweat. On hot summer days, when you're all sweaty and theres a breeze or you fan yourself off...the air blowing over the sweat is making it evaporate, which is what gives the cooling effect. Same thing with the water. Blow air across, and its gonna cool.
However, water stops evaporating once the humidity gets high enough, or it will at least slow its evap rate down.

So by having both fans blowing in, they're going to evap water yes, but then once that water is evaporated, where's it gonna go? it cant really get out too much because both fans are blowing in. By pointing one fan out, wouldnt that "exhaust" all/some of the humidity, while the other fan blows in and continues to evap water?

Evap should not be an issue, even if you dont have an auto top off. All you have to do is make sure that its topped off at least once (2 times is better) per day. Maybe once in the morning before you go to work or school, and maybe once in the evening. IMO, many people just let it go too much, so they feel that they "need" a topoff unit. Yes, topoffs are really nice dont get me wrong..but are they really needed as much as people make them out to be? Maybe on tanks that are evaporating several gallons per day they are, where the person cant be home all the time to do it themselves...but small tanks dont realy evap that much ime. I've got a 2.5 nano that all i do is top off with an 8 ounce glass in the mornings and evenings, and thats with a fan blowing on it.

Mark426 · 09/06/2006, 08:36 PM

Please read my post before yours. The fans dont blow across the water and are SEALED off from any contact with the water. Its hard to explain...just go look at one and you will see what I am talking about. In the old 24 gallon nanocubes, you would be correct. In the 12 Gallon Nanocubes...there is NO WAY the fans can blow ANY air across the water. Its just cant happen.
I have a 12 gallon JBJ nano cube with the 4.24 mod (4- 24 watt pc's) both the fans blowing inward. I loose slightly less than 2 cups of water weekly. My nano tank has been running for 11 months.

Link to a pic of my tank:

http://www.nano-reef.com/gallery/dat...no_8_12_06.jpg

nmprisons · 09/06/2006, 08:38 PM

my neighbor has a 12dx ... I spent a lot of time with him during set-up and he has helped me with my tank. he switched the fans about a month ago and noticed an increase in evaporation (about 10% more or so he says). Why he has a bunch of mods on his tank, I don't see how any of them would effect evaporation.

is it a serious problem? no. is it something to be mindful of? certainly.

I agree completely with Sir.D

Bonebrake · 09/06/2006, 09:32 PM

I switched both fans to blow into the tank and cut 1 1/2" holes into the splash guard directly beneath the fans. It still effectively cools the lights and promotes great air exchange with the water. The default design of the 12 DX is terrible because there is almost zero gas exchange with the outside environment.

sir_dudeguy · 09/06/2006, 09:40 PM

yes i agree w/bonebrake...thats the worste part about them...no gas exchange.
Mark...yes i think it is the older ones now you meantion it...all the people i know have had theirs for some years now, and i dont know of any of them that have gotten a new one in the last year, so other than the ones at the lfs i havent seen the new ones (and for some reason the lfs people dont like you opening their stuff to see what they got lol)

norahs_dad · 09/07/2006, 10:39 AM

Evad 1 I know you asked about the DX modle but I have the older jbj 12 with one strip of lights. I added more lights to the hood after moding it and the temp was at 80.1 with the lights on and would go up to 81.9 with the lights off because I have an extra pump in the back for more serulation when you shut the lights off the fans go off to. I filped the fans last knight to see what would happen . Dropped temp with the lights on to 78.8. I can feel the air comming out from around the hood. tonight i am going to shut the extra pump off and see if it stays at 78.8 I run 2-18 watt and a 24 watt for a total of 60 watts and a moon light under the hood now. Good luck

09/05/2006, 09:57 PM	#1
evad1 Moved On Join Date: Oct 2004 Location: IE, SO CALI Posts: 479	reversing fans in 12 gallon nano jbj dx i heard if you reverse fans in a dx it will run cooler temps does this work? thanks dave

09/05/2006, 11:29 PM	#2
sir_dudeguy Registered Member Join Date: Mar 2006 Location: Portland, OR Posts: 10,841	um...which way do they normally point? lol. Do they point out normally? (like an exhaust only fan?) __________________ TAKE...LUCK!!!

09/06/2006, 07:33 AM	#4
sir_dudeguy Registered Member Join Date: Mar 2006 Location: Portland, OR Posts: 10,841	so they normall point out? If so, switch them around...at least one (if theres more than one?). That will get air in there to cool the water off a little. __________________ TAKE...LUCK!!!

09/06/2006, 02:54 PM	#6
sir_dudeguy Registered Member Join Date: Mar 2006 Location: Portland, OR Posts: 10,841	thats why if theres more than one fan i would only point one in...that way its not trying to force air into a small space thats already got air. But i dont know if they've got 2 fans __________________ TAKE...LUCK!!!

09/06/2006, 05:18 PM	#8
Jim Cannon Registered Member Join Date: Aug 2006 Location: Gilbert/Guadalupe Rd Gilbert, Arizona Posts: 157	What if you had one out and one in? Just curious. I think the idea of the fans is to exhaust the heat from the lights out of the tank and away from the water. So if you change them to blow IN, wouldn't that blow the hot air over the water? Seems backward to me. You put one IN to pull cool air in, thus cooling the lights. The OUT one would exhaust the air heated by the tubes. Seems more logical to me. IMHO. __________________ Jim Cannon Current Tank Info: 55G Fresh African Chiclid, 12G Nano

09/06/2006, 06:23 AM	#3
Mark426 Registered Member Join Date: Dec 2005 Location: South Carolina Posts: 2,479	yup, works. Have them both blowing inward.

09/06/2006, 01:19 PM	#5
schnell76 Registered Member Join Date: May 2006 Location: Central FL Posts: 161	Pointing mine to blow inward, the reverse from stock, helped lower my temp about one degree. I do notice though after doing it that the fans are pretty loud when they kick on. After a minute they quiet down once they get up to speed. It seems like it makes the fans work harder to force the air into the small area. Might be replacing the fans sooner this way, but hey they are cheap.

09/06/2006, 03:12 PM	#7
manse Premium Member Join Date: Jun 2005 Location: Boston, MA Posts: 79	There are 2 fans in the 12DX.

09/06/2006, 07:00 PM	#9
Mark426 Registered Member Join Date: Dec 2005 Location: South Carolina Posts: 2,479	Your right Jim...point both in.....this has been tested by nanocustoms and many people over on another nano forum works best as you have already seen. One in and one out has been tried too....the problem is since the fans are so close together the air never reaches the lights your trying to cool. The air just kinds crosses over form one fan to the other. sir_dudeguy obviously doesnâ€™t have a nanocube and really speaks without any knowledge on this subject.

09/06/2006, 07:13 PM	#10
nmprisons Registered Member Join Date: Mar 2006 Location: Chicago Posts: 1,520	this also significantly increases evaporation so if you don't have an auto-topoff, make sure you monitor closely. __________________ 25gallon tank up and cycling since 7/29/06 Mostly LPS reef (lords, micros, duncans, etc.) with some ricordia florida and zoanthids. Current Tank Info: 25 gallon, 28lbs of Marshall Island and Kaelini Live Rock, 2x65 power compact lighting, IFS Protein Skimmer

09/06/2006, 08:14 PM	#11
Mark426 Registered Member Join Date: Dec 2005 Location: South Carolina Posts: 2,479	Gezzzzzzzzz.... you guys. It wont increase the evaporation at all. Look, the fans are SEALED inside the splash shield. The shield even has a rubber gasket. The fans and the airflow they generate are COMPLETLY isolated from the water in a near airtight chamber on the 12 gallon JBJ Nanocube. I am no expert by any means, but if you dont know what your talking about ...dont add to the confusion please. I am giving up on this forum...too much misinformation time and time again. For good info on nanoreefs ...try... http://www.nano-reef.com

09/06/2006, 08:36 PM	#13
Mark426 Registered Member Join Date: Dec 2005 Location: South Carolina Posts: 2,479	Please read my post before yours. The fans dont blow across the water and are SEALED off from any contact with the water. Its hard to explain...just go look at one and you will see what I am talking about. In the old 24 gallon nanocubes, you would be correct. In the 12 Gallon Nanocubes...there is NO WAY the fans can blow ANY air across the water. Its just cant happen. I have a 12 gallon JBJ nano cube with the 4.24 mod (4- 24 watt pc's) both the fans blowing inward. I loose slightly less than 2 cups of water weekly. My nano tank has been running for 11 months. Link to a pic of my tank: http://www.nano-reef.com/gallery/dat...no_8_12_06.jpg Last edited by Mark426; 09/06/2006 at 08:49 PM.

09/06/2006, 08:38 PM	#14
nmprisons Registered Member Join Date: Mar 2006 Location: Chicago Posts: 1,520	my neighbor has a 12dx ... I spent a lot of time with him during set-up and he has helped me with my tank. he switched the fans about a month ago and noticed an increase in evaporation (about 10% more or so he says). Why he has a bunch of mods on his tank, I don't see how any of them would effect evaporation. is it a serious problem? no. is it something to be mindful of? certainly. I agree completely with Sir.D __________________ 25gallon tank up and cycling since 7/29/06 Mostly LPS reef (lords, micros, duncans, etc.) with some ricordia florida and zoanthids. Current Tank Info: 25 gallon, 28lbs of Marshall Island and Kaelini Live Rock, 2x65 power compact lighting, IFS Protein Skimmer

09/06/2006, 09:32 PM	#15
Bonebrake Registered Member Join Date: Jan 2006 Location: Danville, PA Posts: 519	I switched both fans to blow into the tank and cut 1 1/2" holes into the splash guard directly beneath the fans. It still effectively cools the lights and promotes great air exchange with the water. The default design of the 12 DX is terrible because there is almost zero gas exchange with the outside environment.

09/06/2006, 09:40 PM	#16
sir_dudeguy Registered Member Join Date: Mar 2006 Location: Portland, OR Posts: 10,841	yes i agree w/bonebrake...thats the worste part about them...no gas exchange. Mark...yes i think it is the older ones now you meantion it...all the people i know have had theirs for some years now, and i dont know of any of them that have gotten a new one in the last year, so other than the ones at the lfs i havent seen the new ones (and for some reason the lfs people dont like you opening their stuff to see what they got lol) __________________ TAKE...LUCK!!!

09/07/2006, 10:39 AM	#17
norahs_dad Registered Member Join Date: Jul 2006 Location: cabot , arkansas Posts: 8	Evad 1 I know you asked about the DX modle but I have the older jbj 12 with one strip of lights. I added more lights to the hood after moding it and the temp was at 80.1 with the lights on and would go up to 81.9 with the lights off because I have an extra pump in the back for more serulation when you shut the lights off the fans go off to. I filped the fans last knight to see what would happen . Dropped temp with the lights on to 78.8. I can feel the air comming out from around the hood. tonight i am going to shut the extra pump off and see if it stays at 78.8 I run 2-18 watt and a 24 watt for a total of 60 watts and a moon light under the hood now. Good luck