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fan placement / fixture placement question

2779 Views 21 Replies 7 Participants Last post by  Brian317
Hey all !

So here is my dilemma,

I want to lower the temp on the top of my tank (55 gallon). I have a zoomed HOT5 fixture with 2 non-HO 6500k lights (overall cooler than the HO's) and the top of my tank hits around low 80's, while the bottom is around mid 70's.

Now there is about an inch, inch and 1/2 between the fixture and glass top. Now with the zoomed fixture, it mounts to the lip of the tank and it is as high as I can get it. My first idea is to get a busted tank, take the top molding off and install that on my tank somehow so it can be raised off more. I'm really brain-farting with this one, maybe some other ways to do this? This seems like the better option, but I need it to look clean, as this is in my living room.

Other option, cpu fans. I'm not a electrician, but seems simple enough. I am looking at possibly 2 40mm cpu fans.

Delta 40mm 5VDC Fan AFB0405LD-R00-The Electronic Goldmine

With this power:
12VDC 1200mA Adapter-The Electronic Goldmine
Heavy Duty Adapter - 12VDC 800mA-The Electronic Goldmine

But now the issue, where to place them? I was either thinking one on each end blowing over the top...or both in the middle, blowing outward. How long should they stay on?

My tank in question:

Note: That is not a real frog in the last 2 photos :p

I've been bouncing ideas around, but I've been lacking my creative abilities lately, so if you have any ideas, please let me know. I just want to be prepared.

I appreciate you looking and reading. Thanks
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Hmm, maybe on my own I suppose.

Well after pondering, I think I will build a wood frame to sit the light fixture on. Get a few lumber boards ( 1/2" X 1" or 2") and make something a bit higher, but only 3 sides (back and left/right sides) so I can still get in easy to feed/ect. I'll have to take some measurements when I get home, but what would be best height wise to reduce heat? should I increase height by 1 or 2 inches? What temp difference can I expect per inch?
Hmm, those look interesting. I could just mount to the back of the tank and point them towards the bulbs/ballasts. That could work ! I just need to find them here in the US though :)

Thanks for the post
I did not plan to use the cpu fans for inside, was going to use them on the actual fixture. I have been looking at those actually...just not sure if one would do the trick or if I should get 2 (one for each side of the 55g).

Nobody has fans in stock this time of year (trust me I have looked, all carry heaters now) but if I could find a small personal fan that would drop to top temp a few degrees, I'd be a happy camper.

Do you think raising the fixture an inch or two would have an significant impact on the heat transfer to the tank? Still pondering that idea...
using the fan you linked, with the power supply you linked will almost certainly cause a fire or catastrophic failure of the fan.

...awesome...this is why I ask alot of questions hah

these are available for less than $10 at target. hook it up to your light timer and face it down so that it pushes air between the lamp and tank

I'm sure I can order one online, all my local stores dont sell fans till spring rolls around. Looks perfect. 2 quick questions

Would you think just one of these fans will do the job or should I use two due to the size of the fixture/tank?


I have a plastic divider (splash guard if you will) on the fixture, should I take this off so the air reaches the lamps? Kinda a dumb question, but just wanna cover it all.

Thank you very much all for the assistance
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Sounds great and that is what I need. I'll look today when I get off work.....and sleep that is. I'll check out Amazon too, they usually have some good priced items.

Thanks for the help !
I just recently built a small 18 gallon tank, and am using 4 18 inch t5ho bulbs over it and was dealing with the same issue. I built a "hood" with 3 sides, like you mentioned and my light sits on some "risers" just inside the frame. Since I had lights already in a fixture, I couldn't use them inside a true hood, so this was the only thing I could think of to make it look nice. I then use computer fans to blow acrross the glass to cool it. It looks really clean, and it has to to be in our living room (according to hubby) and I actually really like that it blocks the light from coming out the front and blinding you when you look at it. Then, I have to lift the light fixture off to work on the tank, but the hood stays in place and the glass can lift up with it on. I'm definately no carpenter, but it was really simple, and I plan on making one for my pentagon tank as well. I'll try to post a pic when I get home tonight.
That is exactly what I was planning to do, and may still try even if I get fans. If you have the time to post up a few pics, I would be thankful ! :D

Hey Brian, if it were me I would try to build a frame or something along those lines first. If you design it right you may have the option of lowering the lights in winter and raising them in the summer. If you're still looking for fans here is a site I bought some from last year. I bought some AZOO fans, which I don't see listed on this page. Hope this helps.

Petstore - Search Results for Cooling Fans&modaf=
Yo !

I'm going to see what all I'd need to build one, as I may still try to build something along with getting fans as well. Just a few pieces of lumber, should not be TOO bad....I think hah.

I was looking at AZOO fans. I'm bidding on one now, hopefully I get it and try it out. Seems like a safer way to do it.
I like my AZOO fans. They work nice. I wish they would make them reversible though, at the flick of a switch I mean. I hope you pay less for yours than I did for mine.
Yeah, right now im bidding on a new, but open box and it is pretty cheap so far, hopefully does not sky-rocket in the last 10 mins...

Awesome !! That looks great...hmm...I'll have to think about how I'd like to do mine, but this gave me some inspiration. Thanks for posting a few photos !
Just a little update...

I built a fixture around the top to raise the fixture another inch, top is around 79ish. Fine for winter, but worried about when it starts to warm up...

I looked at the fan James said and I dont have the room for a fan that size, I want to try and get a few pc fans to disperse warm air between the fixture and glass top. I want to watch your video about fans, do you have a link to where I can find it?

I know you said the fans/power supply I listed would fail, but would a 12VDC 500mA adapter be better for one fan? I want to lower the temp, but not to the point I set my house on fire ! I'd like to see James67's video so i know what fan/power to get...I searched a bit today, but didnt find it....
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