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-   -   Cooling ODNO in All-Glass hood? (http://www.plantedtank.net/forums/showthread.php?t=913)

geekgirl 02-25-2003 12:25 AM

Just trying to decide on lighting changes. I currently have 2.5 wpg only when I use the extra hood from another tank. I'd like to set up the other tank (take back the hood:hehe:) and push my lighting to 3wpg on the 55gal. ODNO seems the clear way to go, figuring in the cost of bulbs. A couple questions though,

The lighting needs to rest on the tank so I can't see the bulbs (migraine thing), so will it raise the temperature of my tank or get too hot without a fan? I'd like to do this upgrade using my existing All-Glass twin tube hood fixture, it's vented on top above the ballasts, but no fan of course.

Still a little fuzzy on how much light this actually gives me. With two tubes, to get the equivalent of 160 total watts (about 3wpg on my tank), do I need two 4-F32T8 or two 2-F32T8. Can I reuse all the other existing equipment on that hood--endcaps, power cord, etc? Or do I rip everything out, just reuse the housing and reflector and start new with the rest?

If I do need a cooling fan, can I use one of those little silent computer fans with heat sink? Where would I put it? Anywhere it fits?

Thanks,

Stacey

GulfCoastAquarian 02-25-2003 02:14 PM

I'm using that exact same All-Glass twin strip on my 55g to house a pair of Gro-Lux tubes. It does get hot, as mine sits directly on the glass as well. Tank temperature rises about 2 degrees above night-time temperatures, so it isn't too bad. And that is with a tightly sealed lid (gotta keep those Hatchets from jumping out!).

I don't use a fan with a single 4-F32T8 ballast driving each F40T12 tube 2x. When I tried putting all four outputs to one bulb, though, it got considerably hotter. Using a 2-F32T8 ballast actually underdrives the F40T12 tubes by a good bit since it was only designed to run two 32 watt tubes.

So give it a try with just one 4-F32T8 running each tube 2x, and you might not find that you need a fan. If you do, the silent computer fans with heat sinks definitely work. I'd just put it near the openings in the top of the strip, to push air out of the light strip. You'd need a small transformer to transform 120vac to 12vdc, though.

One additional point, though: with a single 4-F32T8 ballast overdriving a pari of four foot tubes (T12 or T8) 2x each, you won't quite be getting the equivalent of 160 watts. It would be closer to 120 watts. If you got a 4-F32T8 ballast for each bulb, you'd be getting the full doubling power and getting about 160 watts of output.

geekgirl 02-25-2003 06:53 PM

Thanks, even overdriving with 1 ballast 2x each would give the the equivalent of one of those britelites for about 1/4 the cost. I may go ahead and just do that, but I've got DH working on a way to cool the unit so I can go the full 2 ballast 160 watts. The transformer is the issue-kind of spendy. But even if I go that route, the savings on bulbs over the lifetime more than makes up for not going with the smartlite.

Stacey

GulfCoastAquarian 02-25-2003 08:30 PM

I agree, it is a much better deal than the SmartLite. I paid $130 for mine and I could have gotten two of these kits...

Power Compact Ballast and 2 prewired sockets and bulbs $65
For a total of 220 watts (FOUR watts per gallon - phew!) and the same price as the CSL BriteLite/SmartLite fixture.

You don't get the housing or canopy, but I'm going to end up building a nice wooden canopy anyway, so I wish I would have known about that kit back then!

geekgirl 02-25-2003 09:10 PM

Wow! That includes the bulbs? It's a good deal, although still much cheaper over the lifetime going with ODNO if the replacement bulbs are $25 vs. $3. Think I'm going with the overdriven 4x once we figure out how to cool it.

Stacey

Rex Grigg 02-26-2003 01:54 AM

All the light in the world is wasted without a good reflector. That's why I'm glad I went the AH Supply route.

If you look around you can get replacement CF bulbs for about $12 each.

Buck 02-26-2003 02:47 AM

To Get 160w outta that 4'
At H.D. I found a 3-F32T8 and I wired that to 1 bulb and the other I wired with the original 2-F32T8 ballast that came with the shop light giving me the 160watts you are looking for stacey.

Why not build a canopy and dump the allglass ?
I just built one and it was very cheap to do... and it would be even easier to do for a 55 gallon( less cuts on wood)
That way there you have no heating woes to worry about.

I built this canopy for about 45 dollars

geekgirl 02-26-2003 06:20 AM

I may end up building a canopy later, but it's pretty far down on my priority list right now. I've got to reclaim my garage first. It's getting to the point where I can't do any more projects it's so bad.

The All-Glass light housing I have now is adequate and matches but is magnetic ballast of course. I can get the 4F32T8 ballasts for under $20ea at H.D. and found some nice 1/2" maple for a canopy later once I have room to set up my tools again. It would be a good solution for the heat problem. Do you still use a glass top on the tank inside the hood?

Stacey

Rex Grigg 02-26-2003 12:46 PM

Just a note. Just because you are overdriving the bulb 3X doesn't mean you are going to get 3X the light. I have read the ODNO thread and I thought this was pretty clear. You do get a lot more light, but not 3X.

GulfCoastAquarian 02-26-2003 01:11 PM

True, Rex. I've heard this misconception many, many times. 4x ODNO doesn't mean four times the output. It means four times the input power, and since the bulbs efficiency drops as heat increases, you can expect a doubling of output, at best with 4x ODNO.

geekgirl 02-26-2003 07:53 PM

I'm curious what the loss of efficiency is between 3x OD, and 4x OD. If, say, you could get approx 160 off 2 bulbs at 4x, and 145 off 2 bulbs at 3x, is it worth the extra power for 15 more watts?

(Just an exercise in diminishing returns.-HA)

Stacey

GulfCoastAquarian 02-26-2003 09:28 PM

This has definitely not been documented. Even if it had been, every bulb varies, based on size, shape, phosphors, etc.

geekgirl 02-26-2003 11:00 PM

hmmm, what equipment would it take to measure that within an individual lighting fixture? If someone (say me) was willing to take time to wire it up both ways and check. I'm assuming current draw and lumens would do it?

Stacey

Rex Grigg 02-27-2003 01:30 AM

Well a Lux meter would give you some idea.

STAT 007 02-27-2003 08:51 PM

First of all, what is ODNO? Second, I just installed the AH Supply 2x55 Watt fixtures in a $50 All-Glass Black Pine Canopy from www.leisure-time.com that fits my aquarium perfectly (considering it's an All-Glass 37 gallon tank) and holds the fixtures perfectly. It was MUCH easier than building one (for me at least), suited my needs just fine, and looks great. :-)


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