Does It Matter Which Reflector I Use?

[Jaymz]

Looking at reflectors for my upcoming T5 units, the different brand vary from about six quid each to eleven, Juwel to GLO respectively. Does it really make much of a difference on the output which brand I use? Will the more expensive ones reflect better?

Cheers.

 

[smegforbrains]

Not necessarily. Sometimes you are paying for the name.

White reflectors seem to be a lot better than silvered ones.

 

[guppy_man]

Not sure on the brands, but they all do the same job. If it was me i would opt for a white reflector rather than a mirrored one. The white ones focus the light downwards more.

 

[RadaR]

Myself and several other plant enthusiasts have always used the Juwel reflectors. I didn't like my arcadia one.

 

[Rooster]

shiney is shiney - get the cheapest, and how the heck can white do a better job than a mirror ?

 

[smegforbrains]

shiney is shiney - get the cheapest, and how the heck can white do a better job than a mirror ?

It's all down to refraction of the light and the shape of the reflector.

Reflectors shaped in a smooth arc work better than those with angled sides because they have a smooth radius for the light to reflect against.

White reflectors work better than silvered ones because the white is a solid base colour, whereas the silvered finish is not a perfect finish. The silvered finish is applied to the base material (applied to the rear of clear plastic or chrome plated onto metal), hence the imperfections, whereas the white is a solid colour throughout the material (usually plastic). I have seen white powder coated metal reflectors and these are better than the silvered metal ones because the powder coat finish is a lot thicker than chromium plating.

 

[drowning_fish]

so if i was to make my own tabk lid and fit my own t5 lights that are not fish tank designed, then i cover the bottom of the tank lid with a shiny whity plastic type material it would be better than a foil shiny type material.
it will also just be a flat layer of reflector, does this suffice or do i need to arc it in some way?
do ya get me?

 

[Rooster]

Got a "maglite" ? if not, its a torch with a focusable and removable "head"
Remove the head, and you have a bare bulb, place it on the floor.

Walk around it and you will see the light coming from the bulb in all directions (even from above)

Now imagine your face is the surface of the water - yes you CAN see the lamp and its light, but what of all the other light streaming away in the other directions ? Well, its "lost" !

Hold the torch between you and a mirror... now you can see the lamp AND a reflection of the lamp (in the mirror) so you have TWICE the light entering your eyes...
Now imagine 2 mirrors, touching and angled slightly so you can see the lamp in BOTH mirrors... lamp+mirror1+mirror2 = 3 times the light... see where this is going ?

Put the head back on and its curved reflector "mirrors" most of the light out of the front, and the light seems VERY bright from the front
Of course the bulb has not got any brighter... the reflector has simply folded the light from the back and sides of the bulb, to leave the front of the the torch.

So it is with aquarium lamps (or any lamp for that matter) Only about half the light from a tube enters the water, the rest is just warming the hood ! This is what reflectors do, they "fold" the light thats NOT facing the water... and bends it so it does.

A mirror is a very efficient reflector... you can tell this by the detail of the "picture" you see in one - zillions of light rays are reflected from each part of the real world.... a white (or anything other than a mirror) will NEVER reflect as much light as a mirror, so using white paint etc WILL help, but no where near as much as a mirror - or mirrored surface.
Hope this lays a few ghosts to rest !

 

[drowning_fish]

great answer!!

so one more question:
i'm gonna have 4 light fittings,so would it be best to have one large curved reflector or 4 separate ones on each light

whaddyareckon? hmmmmmmmmm

 

[Rooster]

great answer!!

so one more question:
i'm gonna have 4 light fittings,so would it be best to have one large curved reflector or 4 separate ones on each light

whaddyareckon? hmmmmmmmmm

One each...

 

[drowning_fish]

[anyone know any cheap low profile T5 high output florescents with reflectors then?
am gonna hook it up in a way that 1 comes on, then another etc like a sunrise!! pretty cool eh? lol

am i getting a bit geeky with my hobby and my job together!
(controls electrician)

 

[Behold]

great answer!!

so one more question:
i'm gonna have 4 light fittings,so would it be best to have one large curved reflector or 4 separate ones on each light

whaddyareckon? hmmmmmmmmm

4 individual reflectors will be better than on big one as you capture an extra 1/4 of the bulb with a individual protector.

As stated in the maglite example you trying to capture the other 55% of the bulb that is not pointing down in any way and only sideways or up.

A flat mirror will always bounce of at an angle opposite to the source. This is fine for some applications but on an aquarium you need to get the top and side parts to releflect down without hitting the light bulb. by curving the mirror you are providing hundreds of angles that allow the light not to reflect directly back on its self.

With this you need to look for a reflector the covers the bulb about 55% of the circumference of each bulb but not in a full half arc. EG

/\
|o|

but like

._.
/o\

You should hope most expensive ones to have done this but cheap once might not. Just to look out for.

Hope thats not too much waffle and im fully correct. im sure someone will pipe up if not.

 

[Rooster]

[anyone know any cheap low profile T5 high output florescents with reflectors then?
am gonna hook it up in a way that 1 comes on, then another etc like a sunrise!! pretty cool eh? lol

am i getting a bit geeky with my hobby and my job together!
(controls electrician)

An electrician should be THE person who can blag free, err cheap tubes !

 

[Truck]

white is always best, white light is formed from 7 colours and if the reflector was red, the red light would be refracted. but with white all of the colour is refracted back into the water, i mean would you rather have mirror style seats in your car or white, id certainly go for white because it remains cooler in hotter temperature, when there is lots of light, becasue its all being refracted, where as a mirror reflects some of the light not all off it, so white remains most efficiant

 

[Rooster]

white is always best, white light is formed from 7 colours and if the reflector was red, the red light would be refracted. but with white all of the colour is refracted back into the water, i mean would you rather have mirror style seats in your car or white, id certainly go for white because it remains cooler in hotter temperature, when there is lots of light, becasue its all being refracted, where as a mirror reflects some of the light not all off it, so white remains most efficiant

...dont be daft