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Discussion Starter #1
I know there must be some former reefers on here that are using metal halides to light their viv's. If so, how are they set up? I have a pair of 250watt lights that I am considering using on a 65 gallon. My main concern is the extra heat added by these lights. If you use a fan to help cool things down, it seems like that would also lower humidity. For those using MH lights, how are you regulating your temps and humidty??

Thanks,

-Jim Mahaney
 

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One of those lights would probably be enough to cook the frogs in a 65 gallon viv.
I have a 37 gallon (for phelsuma, that like it warm) lit by a single 70 watt halide, and the plant growth is very good.

The pendant is hanging over one end of the viv (basking area) around 3 inches above the tank.
When the light is on, the warm end of the tank gets to the low 90's, and the cool end is the low 80's on the top of the tank, and high 70's at ground level.
PDF's like it cooler than that...most frogkeepers try to keep their tanks below 80 degrees.
From my experience lighting vivs, to keep the temps in a realistic range, 2 watts to a gallon (most of mine have less) is more realistic, whatever the source of light.
Just my $0.02!
 
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Discussion Starter #3
Thanks for the info. I have yet to use the MH lights, so I have no idea how hot they really get. I am thinking about upgrading to a 110 gallon tank, so maybe I could use just one of the 250watt lights on it.

Anyone else using metal halides?

-Jim
 

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I have MH's on my reef tank but even the smaller MH's will possibly cook your frogs even on a big tank like a 90 or a 110. The problem with cooling them is that in doing so you will also be drying out your tank. Maybe if you mount them far enough above the tank but then you'll probably lose a lot of the benefit of why you'd want MH in the first place. T8s, CF's or T5 HO's are a much better bet as a replacement.
 

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Even compact fluorescents can be AWFUL for vivs. Actually, halides are among the most efficient in terms of watts and lumens.

My 2x 55 watt kit will not work for my 40 gallon, unless I want a fried tinc.

The problem is not really heat from the lights, but radiant heat from the greenhouse effect. A muffin fan should do the job fine... Most anurans need high humdity, but the only way to disappate heat from a viv, (which is a mini greenhouse in its own right) is extremely good ventilation and a misting system.

Forget the chiller, they are too expensive and pretty much impractical as they are designed to only chill the water and not the air.

Perhaps if you ever found a way to hook up an AC to the tank, but keep the humidity extremely high, it might be possible. Like Brent Brock said, ventilation/ lighting/ humidity is the most difficult aspect of all in vivariums.
 
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Discussion Starter #6
I have minimal reefing experience myself, but I have to pipe in and say that it seems that the MH or other high wattage reef lighting would be overkill for a dart tank, mostly because they are designed to put out such intensely bright light in order to penitrate the water to the bottom of the tank, which is not necissary in a viv unless it has a rather deep pool and you are growing something aquatic with very high light requirements.

If I'm off base here, someone PLEASE let me know, (I am a newb in many respects to this) but I just bought a 15W 18" flourescent fixture and a recommended tube for plants from OSH for a 25 gallon viv I'm about to construct, and intend to stick with plants that have very limited light requirements. IMO this should severly limit any heat problems arising from the lighting, although I'm prepared to add a 2nd fixture if needed for specific plant types. As I understand it, it's not as much the wattage as it is the spectrum of light being provided that will make the difference in how well the plants grow, correct?
 

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Depends on a number of things. PAR rating, kelvin, full spectrum, and lumens all play a key. Lumens and kelvin apply mostly for our eyesight, however, the higher the lumen rating in a square foot with full spectrum bulbs, the better...in general.

I am not crazy about NO bulbs, because the selection is pretty limited in what you grow. But in order to get some flowering, tropical, light loving types like begonias, impatiens, etc., they need a ton of light and circulation or they grow leggy.

the problem with our hobby is we haven't yet come up with affordable cooling for vivariums OR reef tanks.

If one ever found a way to attach an AC unit that wouldn't corrode with all the humidity, (and you could keep the humidity high) it would work.

Those 18" striplights are pretty useless unless they are within 6" of the plnt tops and the plants are low growing.

I'd go with a 2 x 13 watt bright kit to start. Unlike my 2 x 55 watt cf over my 40 gallon, it only raised the ambient temp about 2-3 degrees (in my experience). Just be careful if you want to increase the wattage you don't increase radiant heat from radiation from the bulbs.
 
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Discussion Starter #8
Ok, my tank light will be sitting about 12" above "ground level". It's an 18" 457nm 15W flourescent light with 510 lumens of output. Being a small enclosure (25 gal) I intend to stick with low and low/medium light requirement plants.

Opinions and suggestions?
 

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Arachnid said:
I have minimal reefing experience myself, but I have to pipe in and say that it seems that the MH or other high wattage reef lighting would be overkill for a dart tank, mostly because they are designed to put out such intensely bright light in order to penitrate the water to the bottom of the tank, which is not necissary in a viv unless it has a rather deep pool and you are growing something aquatic with very high light requirements.

If I'm off base here, someone PLEASE let me know, (I am a newb in many respects to this) but I just bought a 15W 18" flourescent fixture and a recommended tube for plants from OSH for a 25 gallon viv I'm about to construct, and intend to stick with plants that have very limited light requirements. IMO this should severly limit any heat problems arising from the lighting, although I'm prepared to add a 2nd fixture if needed for specific plant types. As I understand it, it's not as much the wattage as it is the spectrum of light being provided that will make the difference in how well the plants grow, correct?
I'd say you are pretty much on track. The largest factor for plant growth is light intensity roughly within the visible light spectrum excluding green. My personal feeling is that as long as you don't exceed the intensity of full sunlight, you are okay assuming you have plenty of plant growth to create shady spots for the animals. I'm guessing an MH light is the only thing available that can approach the intensity of PAR comparable to full sunlight. So the light output of MH doesn't really bother me, it would be fantastic for orchids, but what would you do with all that heat other than fry frogs and plants? Like Rainfrog said, even cooling a viv lit with CF can be a challenge. I guess this is a long way of saying that I agree with everyone else that the MH may be overkill.

However, I've never played with MH myself and have a question. Suppose you were building a vivarium that was about 10 ft. tall. What would you use for lighting? Planck's law says that the intensity of light diminishes with the square of the distance from the source which means that you need a pretty intense light source to push enough PAR to grow plants at the bottom of a 10 ft. space. Would MH work? And where is most of the heat generated? How much is from the ballast and how much from the bulb? How close can you hold a bare hand to an MH bulb without getting scorched?
 

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Hate to interject with some real physics, but when you get to high intensity lighting, if the lights are outside the viv (glass or acrylic between the light and the vivarium space), it is the light itself that will be heating up the tank. Most of the IR spectrum will be absorbed by the glass, but once the light is absorbed by the contents of the viv, the effect on the heat is the same. 1KW is 1 KW, whether it comes from a heater or a laser. Even if you only input visible light, anything even approaching full sunlight would cook a tank in a flash (sunlight is ~1KW/Sq meter).
 

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If you built a cool tube to extract the hot air from the outside of the bulb you can bring down the heat considerably. The bulb is placed inside a hurricane glass tube and 4" dryer duct is attached to each side, and a powerful fan blows through the tube carrying the warm air away from the tank.
 

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geckguy said:
If you built a cool tube to extract the hot air from the outside of the bulb you can bring down the heat considerably. The bulb is placed inside a hurricane glass tube and 4" dryer duct is attached to each side, and a powerful fan blows through the tube carrying the warm air away from the tank.
That will help, though I've heard it isn't good for the performance of the bulb to have a fan blowing directly on it, something like the arc is designed to operate within a certain temp range...something like that.
 

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I will repeat again, the problem I have had, that I completely forgot about, is not the by product of bulb heat, but radiant heat from light.

Vivariums do not have wind, clouds, oceans, etc. to keep temps stable from the constant radiation of the sun.
 
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Discussion Starter #14
I've been reading a lot lately on this site about using cool mist ultrasonic foggers along with European ventilation tactics. I don't quite understand it all yet, but I'm learning...

Anyhow, a dumb thought occurred to me! Anyone thought about making a miniature "swamp cooler"? For anyone who's never heard the term, it's the poor mans AC and creates a lot of humidity while cooling a room in the summer time, so why couldn't a smaller version be jury rigged for a tank? Essentially the concept is simple enough: cool water trickles through the course pads covering the air intakes by way of a water pump in a sump, and a fan sucks the air through the pads, both cooling and increasing humidity in the air being pumped into the environment. If the ambient room temps are in the low to mid 70's then the water temps would likely be slightly cooler than that in a decent sized sump, right? I may be way off, but it seems like it would be blowing humidified air into the tank instead of dry air, and that air would be cooler than the air already inside, countering the greenhouse effect you are talking about. I doubt it would work for ten gallon, but for larger tanks it seems feasable.

Any thoughts on this?
 

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other people have thought of this technique, but it generally has resulted in failure. The biggest problem is the fact that all those cooling devices, even chillers, need to be set on an expensive temperature controller (like reef tanks do). Even if it is effective, all you're doing is creating a big draft in the tank that can be lethal to animals. Plus, the humidity will still not be high enough unless you have misting system.

Another problem is the fact that evaporative cooling doesn't work unless you have low humidity, as it needs an open circuit. You MUST have a circuit for the hot air to blow out, and allow the cool air to move in.

AC is generally better, as it will recycle the air...it needs a closed circuit. But the bad thing is, frogs need ventilation, so you still need some air movement. One reason why chillers remain so expensive is because of the titanium needed for heat exchanging in the water. A normal AC experiencing that much humidity could corrode the copper piping inside.

This had led me to another topic......has anybody attempted raising their frogs in wire cages in a controlled greenhouse?!?
 

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Rain_Frog said:
This had led me to another topic......has anybody attempted raising their frogs in wire cages in a controlled greenhouse?!?
I've thought of that before, (what I thought of was a room in a basement with a single, large MH light) and would like to try it when I get my own house/property.
I wonder if the screen would get as cruddy as the glass usually gets.
 

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You know, I do believe there is a method to keep cool (and cheaply), but it is pretty bulky.

A/Cs do not need to be submerged in water. In fact, the copper coils corrode. Dehumidifiers, however, do not corrode in water, as they are aluminum (except saltwater).

Perhaps if one built a unit that connected up to a vivarium on a temperature controller, it could work very well. (as long as nothing corrodes from high humidity).

The coils would directly be placed in the vivarium air, but perhaps it should be sectioned off with screening or something else to prevent animals from getting near it.

Additionally, one must need to have double panes of glass/ acrylic in order to insulate them better. The sides could be made of wood or styrofoam around the tank for good insulation, but there would still be a need for air circulation.

This sounds pretty technically challenging, probably only suited for large vivaria, but those plant fanatics sure would like an alternative to the expensive chillers on most reef tanks (which only cool the water, not air).
 
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Rain frog, can you elaborate on this a little? I'm not quite following you here, but it sounds interesting.
 

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Basically, an AC unit's coils are suspended in air, they do NOT need to be submerged like a heater needs to be. (thats how the AC works) The negative side to this, if they ARE submerged, at least in saltwater, they corrode.

What makes a chiller so costly are the titanium coatings (to resist corrosion but provide maximum heat exchange), the temperature controller, and compact size.

Now, in a freshwater environment, I am not sure. Mostly, because we use copper pipes for water. Copper is harmful to invertabrates, so potentially it would be safe in a sump of a water feature for anurans...

However, I cannot use this idea for my Xenopus tank. Clawed frogs hate metal, and i do not know if Dendrobatids or hylids are sensitive.

http://saltaquarium.about.com/gi/dy...ium&zu=http://www.guarriello.net/chiller.htm

Final note. If you were able to find a way to get the AC coils into a vivarium (best a large one), section it off to prevent animals from getting in there, buy a good temperature controller for Reef tank chillers, it could potentially work very effectively. Many folks that have made their own chillers report that it is FAR more efficient...if they have the know how and can do something about corrosion, space, etc.

Regardless, you will STILL need to buy an expensive temp controller.

Even if it works well, keep in mind that many frogs need a drop at night. That's my drawback as i have never used a temp controller, and not sure if they are designed to run at a constant temp, or if they can slowly drop a temp. However, some support cooled water more instead.

Why? Because the tank's temperature would stay much more stable due to the nature of water. The downside is, if the water is too cool, and the animals fall into the water feature, that could be bad. But, I'm sure if you get your circulation established, that shouldn't be a problem. Additionally, water is slower than air to change in temperature, so making it cooler at night may not shock the frogs as much relative if you turned the AC down 10 degrees at night for vivarium air.
 
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Discussion Starter #20
although i have not used MH lights in small enclosures, i have used them extensivly in large and medium sized vivaria (12'X12'X8' and larger). i used combinations of mercury vapour and sodium vapour 500 and 1000 watt units as well as banks of cool white fluoescent. The lights were sequenced to simulate dawn and dusk. The radiant energy is substantial so good air movement is essential to keep plants growing near the light from cooking. I used redundant automatic forced air venting to exaust air when temps reached a threshold. canopy plants like bromiliads and orchids thrive with the high light levels near the upper levels (1000 lumins+). The secret is having a stable thermal mass to prevent wild temp swing and fairly good coupling to that thermal mass.
 
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