T5s Q&A

I personally would recommend 4 Aquablue+ and 2 Actinic+ or 3/3 of each if you want a more blue look. I you want more white thry 3 Aquabue+, 2 Actinic+ and a 6,700k bulb. Either of these combos will fetch you nice PAR and growth rates, the main thing now is to determine the spectrum you wnat in the tank.

Good luck
Oh the said bulbs are Gieseman....

 

thanks for the advice ,i am still useing the old t-12 blue bulb and 2 t-8 white bulbs .i dont what they are and for now dont care as they are going to be replaced( i have no corals just FOWLR)i had this tank dropped in my lap.what would be a good light fixture for a standard 29 gallon tank.sorry if i am kinda stealing your thread here.

 

Any more???

 

What size tank? I would think a couple of ATI Blue plus would be fine to replace actinic. I ran the UVL Super Actinic T5 with a SE MH and didn't care for them.

 

I would say if you are replacing 2 65 watt pc you could use 2 39watt 36" T5's running on a regular ballast. Still is going to depend on the kelvin of the t5 and length of the bulbs you want to run.

 

Thats one of those questions that has been asked and asked and no one ever answers it with a straight answer. What I can tell you this, for those that know about lighting this will be slightly elementary...
Lighting in our tanks is meant to first and foremost, allow us to view the tank, but for people that keep photosynthetic creatures it serves a dual purpose, to create PAR for the creatures to utilize. PAR is photosynthetically available radiation, and its what plants and other photosynthetic creatures use to grow and prosper. Lighting in the aquarium is typically one of three types, metal halide(MH) compact fluorescent(PC or CF) and T5(named for the diameter of bulb).
The amount of PAR produced by any of these lights is a determined by a few factors, bulb itself, reflector and ballast.
Better bulb, ballast and reflector of any of these lighting types can potentially beat a VERY lousy combination of the others. I say potentially as it is nearly impossible to create a "perfect" reflector for PCs and until that happens it will no matter what be at a disadvantage that way.
Getting back to your question missionsix, one way to compare lighting types is to set up identical tanks and have the same wattage of all three lighting types on each of the tanks. Meaning 300watts MH on a tank, 300watts T5 on a tank and 300watts PC on a tank, then compare the PAR. There is so many factors still, what brand bulb do you use, or ballasts and reflectors? There is much variance in the same lighting category, it would be a tough test to set up.
You could also set up three tanks like before, but instead of having the same amount of wattage, shoot for the same amount of PAR in the tank, (that would be incredibly difficult if not nearly impossible..) and then compare wattage from each light.
I know it doesn't quite answer your question definitively but I have a post that might......

 

The problem is that the efficiencies of different bulb technologies vary depending on the spectrum.

For instance, the mfg's rate them at 3000K...

-PC technology tops out at about 60lumens/watt

-T5 technology tops out at about 95 for T5NO, and 85 (I have heard claims of 90) for T5HO.

-Halide tops out at about 105 lumens/watt. I have heard 115 lumens/watt stated for the technology, but never on an actual mfg's specs.

-Plasma or Sulphur Vapor bulbs are supposed to top out at 150 lumens/watt, but are almost impossible to get at a spectrum any lower than 6500K.

-LED's are topping out at about 150 lumens/watt as engineering samples, and I forget since I havent looked at any specs since I tested the AI88 LED unit, but the ones on the market now are a fraction of that in output.

Also keep in mind that lumens is a measure of the brightness according to what WE SEE. In daylight conditions, we see green the best, and then red, but only a small part of our cones are there to see blue (about 10%). So for corals and other organisms, we use PAR, which measures all frequencies evenly from 400-700nm (the visible range), or sometimes an extended range which includes UV and IR (about 280 to 800nm). This is also what is best for corals, because they rather happen to like the blue spectrums...lol. The only problem is... lighting companies dont tend to advertise spectrums we cant see. So as any bulb goes from say, 3000K to 20,000K (marketing terms at that with no specific requirements for spectrum), the lumens take an unfair dive.

Here is maybe a better way to explain it:

Bulb A is 3000K, and bulb B is 20,000K. Bulb A has a lumen output of 3000, and bulb B has a lumen output of 800... but the PAR of bulb A is 200units, and bulb B is also 200 units. All the blue output that bulb B makes IS THERE, but the lumen scale (photometric) doesnt measure all spectrums fairly... the PAR scale, or radiometric scale, does.

Also, blue bulbs due tend to have lower efficiencies. This is because the higher the frequency (the smaller the wavelength), the more power it takes to produce the same photon. So even if a bulb technology could convert energy at all frequencies evenly, since blue light contains more energy, it also takes more to produce. So the PAR of many 20,000K halide bulbs is usually about 1/2 of what the 10,000K is. But this is where things get crazy...

Phosphor/linear lamps rely on a mix of gasses inside the bulb to produce light. This light is not the end product though (unless you want a UV-C lamp), as it is really there to excite the phosphors on the inner surface of the bulb, and these phosphors convert the radiation into the visible spectrums we want. So its a two step process... and there is a conversion going on. As a consequence, phosphor based lamps, which start at the bluer end of the spectrum (hey, if we just wanted those spectrums, they would be waaaay more eficient than any halide), the phosphors that make blue light are very efficient (minimal conversion), while the ones that make warmer spectrums arent as efficient.

Halides are a pure gas that you are arcing electricity through... no conversion. And the halides that are used tend to be rather true to the energy conversion... so they suffer drastic cuts in output when you go from 3000K to 20,000K.

T5s tend to be better at making blue, and halides are better at making warmer spectrums. As you go towards the blue end, the blue+ style T5s are much better at making blue than halides, but halides trump for output in the warmer spectrums. For our reefs, we tend to have bluer spectrums... a mix of daylight and blue, okay, alot of blue. So to say that halide is better or T5s are better... hard to say... depends on the spectrum. The best of both worlds is usually to use a 10,000Kish halide and flank it with multiple blue+ style T5 bulbs.

As for T5s vs. PC, there are also other things to mention. Remember that 'plasma vapor' technology I brought up? They are wicked bright lamps, but also very very hot... so hot that they need blowers to keep the bulb cool (and the electrodeless bulb spins to spread out the energy from the magnetron) or the bulb would melt almost instantly. Due to the limits of magnetron technology (a microwave), the wavelength and focus are rather large, so a large bulb is used... usually 1500 watts on up. Such a bright bulb in such a small area isnt very useful though, not when you add up all the extra fans and motor to keep the bulb spinning. As a result, the bulbs are often placed in 'light boxes' and the light is piped out via fiber optic cables. By the time its all said and done, the effective output of the technology is worse than PC or VHO because so much is lost in the delivery system. Similar things could be noted for PC vs. T5...

Sure, T5s are about 50% higher output than PC's, but its not just that. The 'bend over' profile of PC's pretty much means that a good amount of the output from the bulb is spent lighting the other half of the bulb. The light that goes elsewhere is hard to control then... to make an effective PC reflector, well... it just doesnt exist really. With T5s, their narrow profile allows for 2"-3" wide individual parabolic reflectors that focus nearly all the light downwards, and sometimes into rather well focused rays. Still, there is some loss from the reflecting material and varying focal points, light that spills out at useless angles, etc... but its still loads better than PC or VHO bulbs. Beyond that, T5s have had their phosphors engineered to last much longer, at higher operating temperatures than earlier phosphor lamps, and T5 cooling technology is much better as well. The cool thing is that the 'high efficiency' ballasts for T5s havent even hit the market yet.... it takes a while for that. T8's, T12's, VHO... they all have the 'high efficiency' spec ballasts because they have been around long enough... T5s dont yet, and they already put the other's to shame and give halide a run for it.

Then there are LED's... crappy performance, but an awesome delivery system. They may not make alot of light, but the surface is already focused in one direction, AND the 'bulb' itself acts as a fiber optic lens so that nearly all the light that the LED does make is focused like a laser in one direction. Also, they are phosphor based, and tend to be rather good at making blue light... blue is a LED's best spectrum. As a consequence, their effective output is very similar to halide. Note, Im talking output per watt here... so the AI88 unit (actual wattage of 95) is not going to replace a 250 watt halide (like some claim). Rather, if you had 250 watts of them, they would match the output of a halide (And I should be specific here because it matters, a 1 month old pheonix 250wattDE 14,000K in a Lumenarc 3 mini reflector). So no, I will not re replacing my $300 halide pendant with a $1000 LED unit any time soon since the HQI is 320 actual watts, and the LED is about 95... and their outputs are just as proportional.

Also consider the subject you are lighting. A halide pendant is more like a 'point source', as in, its rays of light travel outwards in a sphere. Now, a reflector augments this, but then compare a T5 array... the light source is linear, and with the reflectors and multiple bulbs covering the surface, the light travels in a more parallel manner... making a planar field of dispersion. Why is this important? Well, in distances more than say... 4x the length of the bulb, the light intensity from a point source drops off very fast (look up the inverse square law). The more parallel rays from a T5 unit tend to travel further then because they are a larger source. That 'shimmer' you see from halides is actually an indication that they are a light source which will not carry as far, as in, more of a point source. The less shimmer, the further the light will carry, or penetrate into the water. This also depends on how much the glass walls of the tank reflect (acting like a reflector), as well as things inside the tank (black sand vs. white for instance). Anyways, long story short, halides, since they tend to cover less of the water surface and get mounted up higher, tend to illumiunate the canopy or room they are in with a good deal of their output from how it reflects off the water surface. T5s tend to cover more area, and if you look above a T5 lit tank, they tend to be rather dark above the T5s... a retro in a canopy tends to be alot darker than with a halide, so more light is going into the tank... keeping in mind that with T5s, you can be 2" from the water surface with the bulb and have an array that covers the whole water surface. This could be seen as a good argument to add polished aluminum 'blinders' that extend from the bottom edge of your halide reflectors down to the edges of the tank parimeter to recapture and redirect the lost light back into the tank. I have seen enough PAR readings to suggest that some halide setups end up wasting a good 5-10% of their output on lighting up the room or canopy rather than the tank.

So there is no clear response to your question. Lumens isnt an accurate method of measuring, esp when you start to get into bluer light... PAR is the only accurate way to measure. The actual output efficiency of a bulb technology will vary depending on the spectrum (different technologies have different strong spectrums). And then there is the delivery system (reflector) to consider, and this in itself can vary depending on what you want to light... LED's make excellent spotlights by their nature, and plasma vapor bulbs suck at being spotlights... regardless of their efficiencies.
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Regards,
Jonathan 'hahnmeister' Vincent Banannahammock of Wannapikapipi, Kainawannalaya Island, Hawaii.

Quoted from Jon Manke, extensive lighting tester