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Discussion Starter · #1 ·
just wondered why "bent" or parabolic reflectors are used instead of just half circle or radius reflectors... seems like the amount of bends is supposed to make a reflector better(referring more to t5 than mh) so with that logic a radius would be equal to an infinate amount of individual bends, and the light would reflect at every possible angle. that would be better right? been thinking of experimenting with this if i can get some of the reflective material used for high-end reflectors(any ideas of where to look?). i have a 2.5" mandrel at work thats 6ft long that i could make a couple sweet reflectors with.

any input on this?
 

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the location of the bulb in the reflector is critical. the light is not canceled out, it is blocked by the bulb and it causes additional heat on the bulb. this is a major factor limiting the usefulness of retrofit kits because the bulb is not in the correct spot after mounting. the correct window for bulb placement is very small and is diffrent for each bulb.... ie the placment for one type of 250mh is not the same as another let alone a smalller or larger one. the best reflectors for vho bulbs are the ones already built in!!!!!!
 

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the location of the bulb in the reflector is critical. the light is not canceled out, it is blocked by the bulb and it causes additional heat on the bulb. this is a major factor limiting the usefulness of retrofit kits because the bulb is not in the correct spot after mounting. the correct window for bulb placement is very small and is diffrent for each bulb.... ie the placment for one type of 250mh is not the same as another let alone a smalller or larger one. the best reflectors for vho bulbs are the ones already built in!!!!!!

Ok well note he is talking about T-5's and not about VHO's, and being blocked by the bulb is in fact being canceled out due to the fact that it is not being reflected into the tank but back into the bulb itself. Right or wrong ?
 

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Discussion Starter · #5 ·
i see what both of you are saying. im sure i could get the bulb in the right placement, and i think its time i get new bulb clips for the reflectors that i have... some of my reflectors arent perfectly straight and i didnt know it made a difference.

if the light is reflecting back into the bulb then thats no good. looking at my icecap slrs though its hard to believe that the light doesnt reflect back into the bulb in the same way.
 

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t-5's are new to me so i was not going to comment on their use directly, but go with an angle that i have experence in leaveing room for information that may be the same. vho's and t-5's are the same shape just smaller in dia so the reflector should be very close.
 

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This is a very interesting question. I was thinking about getting a new T5 fixture for my 40 gallon FOWLR tank in case I wanted to add some corals to it. I have seen the fixtures with a single reflector for the fixture and then the ones that come with individual reflectors for each bulb. The bulbs are the same, 36" is 39 Watts, yet the prices are very different between the fixtures.

So, for the difference in money are the individual reflectors really going to make that much of a difference?

I think that is sort of what you are asking as well. I am not trying to hijack your thread and hope this doesn't take it off course.
 

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I think the biggest thing to do is to direct the light around the bulb and down into the tank no matter what type of bulb it is and Savjays website will show the same info, As he test all types of bulbs and different reflector types so with my hands on exp. the reflector is just as important as the bulbs we use, I went from regular spider reflectors to lumanarcs and the difference was like night and day.
 

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Here is the difference:



This is showing light being collected, yet think of it in reverse.

Spherical, or radius with a linear light source, will have a focal plane. This means that there is no single point or line in that reflector that you can place the bulb to reflect 100% of it back in a straight column of light, the light will either converge or diverge.

Parabolic reflectors have a focal line, this is where the bulb is placed to reflect all the available light in a straight column.

If the bulb reflectors are packed tight enough to touch each other, parabolic is a better option, if not then I would go with spherical.



T5's do better over PC and VHO because they emit light from a single smaller diameter, hence a more linear light source.
 

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