TEK T5 reflector claims a little high?

[Aquabucket]

I just got done doing some more research on T5 reflectors and light output. Here is a link (http://www.sunlightsupply.com/aquarium/products/t5reflectcomparo.shtml) to a test used to make a claim that TEK reflectors basically make one T5 bulb as bright as 4 bulbs or 300% more light output.

I just do not see how this is possible? First off the reflector only can reflect the top half of the tube to begin with. Second they used a lux meter to determine the reflectors effectiveness on a reef tank.

Quote: "Lux as a means of measurement is not ideal for measuring light sources for use with aquariums (or for horticultural purposes for that matter), because it measures the output of a light source against the human visibility spectra and not that of photosynthetic plants/animals. However, it is justifiably used when seeking differences in measured output between reflectors."

My question is why didn't they use a different type of meter? Could it be that this test helped skew things their way?

How penitrating can this reflective light be when water is involved? Take in mind that their testing did not involve water. Also what kind of spectral shifts can occur with reflective light?

How effective are these reflectors with actinics? No test there.

Anywho I realize TEK reflectors can increase the output of already powerfull T5's but 300% in a 2" wide space?

I just find it kind of hard to believe and would like some more independent testing to be done before a claim can be made that these relectors are like adding more bulbs.

Anyone here experment much with T5s and reflectors?.

I have a T5 6 bulb set-up with a flat reflector and it is blinding. I can't imageine what 300% more reflective light would look like.

It would like to hear your comments.

[Rikko]

I wonder that myself. I suppose it really depends on the distance that the bulbs are from the tank. If they are at the water level, you essentially get 50% of all emitted light going into the tank. Farther away and you begin to lose it because of the angle (simple geometry).

I guess if they benchmark the "tank" as, say, 18" from the lights, and the reflector wraps around a bit (I've yet to see a very good pic of those reflectors) that they could make a case for the light also bouncing from below the "half" line of the bulb and redirecting more of it into a tighter area.

I'm still a bit dubious, but they definitely reflect the light!

That said, I built a canopy with NO T5s in white PVC tubing and the light reflected is incredible. Better than the simple strips we have in the shop, and that's really only because of the shape.

Oh, my strip also has a single actinic in it, and I find that the reflector works very well with it. The blue "lightens" somewhat, but since it's bouncing off a white background I suppose it stands to reason.

[Obi-dad]

Actually, without a reflector you do not even get 50% of the light into the water, since beyond a certain angle of incidence to the water the light reflects off the surface instead of entering the water.

[Aquabucket]

More reason to doubt TEK's bold claims. If the direct lighting from the bulb is reflected at the surface it stands to hold true that a certain % of reflected light would also be bounced back from the water.

Don't get me wrong though, TEK reflectors appear to be the best reflector available for T5s. I just doubt their ability to add 300% more light to your tank as the test was conducted without water or a par meter.

[moonpod]

lux meter vs a par meter just biases towards visible spectrum light. It's still a "valid" way to measure light output, in particular for "daylight" bulbs.

The test is conducted in air, b/c frankly it reduces variables. Most light testing is (see sanjay joshi, jb ny, traveller 7, etc...)

The nice thing about the SLS test, is that you can do it yourself. It's VERY simple. Lux meters are readily available from photo stores. It's reproducible. The numbers really do jump quite a bit from no reflector, to flat and simple U reflectors to the Tek reflector. I haven't formally tested the IC reflector, but my guess is that it's in the range of the Tek reflector as the geometry is practically identical.

[Aquabucket]

Thanks moonpod. Did it appear that the TEK reflectors quadrupaled the brightness? Is it really that dramatic of a difference in your tank?

Also what brand actinics are you running and how do you like them?

[moonpod]

Visually no. By the numbers, it ran inline with the SLS testing.

I'm doing a mix of things b/c I'm doing something screwy with my lighting. One half of my tank is primary lighting XDE 10k. The other half is the AC 14k. I'm supplementing the XDE 10k with the ATI blue plus, and the AC 14k with a mix of helios and ATI actinics. I was using the ATI, which I like, but I am experimenting/comparing the Helios.

[Obi-dad]

Aquabucket, I may not have been very clear with what I was saying about the light at high angle of incidence to the water.

Imagine a bulb with no reflector above the water. Almost all of the light that is directly downward goes into the tank. As you get farther away from the bulb more and more of the light is reflected from the surface, so you are getting less than 50% of the total light entering the water, since half isn't even pointing to the water, and some of the rest is reflected.

With a bulb in the Tek or IC reflector, much more of the light is directed directly downward into the tank (even the light coming out of the top side of the bulb due to the shape of the reflector), so very little is reflected off the surface of the water. This is how the reflectors make such a huge difference.

[manderx]

the reflector helps get around the law of inverse squares. without it, the bulb acts like a point source, so the intensity drops by the square root with distance. the reflector changes it from a simple point source to a beam that doesn't disperse as quickly with distance.

[skippyreef]

I am getting a quad retrofit of the tek lighting. I have never used T5 before so this has been helpful to say the least.

[Rikko]

Thanks Obi-dad, that makes a lot of sense.
So in effect the "bottom" 50% of the bulb may have, say, 30% waste light. That is never reclaimed. What is gained to get >100% light increase is the way the reflector takes the rays that would be bouncing off the water surface of the other side of the bulb and changes their funny angle to straight down, thus negating that.

[Aquabucket]

Oh well, I am still happy with my flat reflector. I did some measuring and I could only fit 3 T5s with reflectors in the same space that I have 6 bulbs now. I really wanted to experiment with different bulbs so I wanted 6. The TEK lights were too wide for my set-up. I like to have room at the front and back of the tank for easy access at all times and for better O2 exchange & cooling. With a 12" wide tank the 7-1/4" profile is just right for me.

All I can say is this. 6 HO T5 bulbs in a 7-1/4" wide hood are very intense (1/4" space between each bulb), especially on my 30G tank.

My HO 10,000K 39W T5s look much more intense than the 10,000K 65W VHOs that I was running before. Right out of the box they pack some juice.

You can't beat the reflectors though for efficiency, so I would go with them if I had a wider tank.

I plan to keep a mixed reef with only a few SPS sprinkled in and maybe a clam or two. I am confident that I have more than enough light on this tank to acheive great results.

Thanks all for your comments.

[mikester]

Yeah, in your case you are probably not losing too much, other than just the extra electricity for running 6 bulbs instead of 3.

I'm curious how you are fitting that many bulbs in such a small area? You must not be using the waterproof endcaps, because the standoffs for those are 2.5" wide (which is wider than the individual reflectors).

[Obi-dad]

I also pack T5s in closer than the 2.5", because instead of using the waterproof endcaps I use push-on Molex pins covered in heat shrink tubing. This way I can put the reflectors edge to edge.

[Aquabucket]

No water proof endcaps as they will not be exposed to water because of an acrylic splash shield. The bulbs are 1/4" away from each other. The endcaps do have a twist/close feature. If I encounter any trouble I could coat them with some vasoline.

The unit is basically a Coralife Aqualight with 6 T5s, a flat reflector, and 3 Workorse 5 ballasts. I modded it with 4 built-in 12VDC fans (2 on each end for a push pull config) and rearranged the lights for a better dawn/dusk mode. Bulbs 2&5 now fire as opposed to 5&6. The bulb's endcaps were riveted so I drilled them out and replaced them with nuts and bolts.

The whole unit comes apart easily by removing 6 screws.

I did some recalcuating and only 2 T5s with reflectors could fit in the same space so I am happy with my purchase and I guess that's what matters most.

[MiddletonMark]

My experience upgrading my MH reflector was one of significant bleaching.

Maybe this reflector is slightly overstated ... but on MH reflectors I seem to recall Sanjay Joshi getting 30% + more light from the better reflectors [and on a point source, IMO a tubular light would work significantly better].

It's your power bill, your replacement bulbs ... but my experience with MH + PC reflector upgrades was striking. I actually decided to skip on T-5's, as the reflector [which IMO makes the bulb `better' than others] could not fit with my MH's.

[Aquabucket]

Originally posted by MiddletonMark
It's your power bill, your replacement bulbs ... but my experience with MH + PC reflector upgrades was striking. I actually decided to skip on T-5's, as the reflector [which IMO makes the bulb `better' than others] could not fit with my MH's.

I have to say my T5s have much more intensity than my PC/VHOs that have double the wattage. So right out of the box that is an upgrade for me. As far as replacement bulbs I really wanted more for variety and experimentation.

I don't doubt that the right reflectors increase the intensity. I just don't really need any more light in my case (8 watts per gallon of HO T5s). I am just not doing things as efficiently as possible. The trade off is more space, a wider selection of bulbs and I burned a smaller hole in my wallet. (I received 13 bulbs with the unit because of a shipping error).