how deep does this work to?
- Thread starter A_Lee
- Start date
Tumbleweed
Guest
I run 2 250W on my 20 deep tank
Gomer
Guest
And it also is highly dependent on the reflector you use.
...you may not want to read the following lol.
The whole light penetration deal is about how much light you can get down to the bottom of your tank. Everyone argues that brute force (more light) is the solution. This is where the 175 for X depth, 250 for Y depth and 400 for Z depth comes from.
A point source light decays as 1/d^2. A point source would be no reflectors. As you double the distance, the intensity drops off by 1/4. triple the distance then 1/9 etc.
A perfect point source in the focus of a perfect parabola has no decay (ignore coherence) over normal distances. That is to say as you go from 1" to 10ft, the light intensity is the same.
1) a reflector system is somewhere inbetween. It is neither a point source, nor a perfect parabolic source and its decay rate lies somewhere in between. Where in between is dependent on the reflector design.
2) a perfect light system (point or perfect parabola) aren't perfect when you toss in a tank. chaotic reflection from the water surface, total internal reflection from the glass, and scattering from items in the tank all change everything making it more convoluted.
In an quasi ideal situation, you want to use a big reflector that directs almost all of it's light down. This helps prevent the loss of light from transmission through the glass, and the massive amount of spill that we constantly encounter. The large lumenbright and lumenarc both attempt to do this. They both have their pluses and minuses from a pure design standpoint and that is a whole different post
Using a good and appropriate reflector on a 250 can easily get you more uniform light from top to bottom and more penetration (intensity at the bottom) then a 400watt with a crappy reflector
...you may not want to read the following lol.
The whole light penetration deal is about how much light you can get down to the bottom of your tank. Everyone argues that brute force (more light) is the solution. This is where the 175 for X depth, 250 for Y depth and 400 for Z depth comes from.
A point source light decays as 1/d^2. A point source would be no reflectors. As you double the distance, the intensity drops off by 1/4. triple the distance then 1/9 etc.
A perfect point source in the focus of a perfect parabola has no decay (ignore coherence) over normal distances. That is to say as you go from 1" to 10ft, the light intensity is the same.
1) a reflector system is somewhere inbetween. It is neither a point source, nor a perfect parabolic source and its decay rate lies somewhere in between. Where in between is dependent on the reflector design.
2) a perfect light system (point or perfect parabola) aren't perfect when you toss in a tank. chaotic reflection from the water surface, total internal reflection from the glass, and scattering from items in the tank all change everything making it more convoluted.
In an quasi ideal situation, you want to use a big reflector that directs almost all of it's light down. This helps prevent the loss of light from transmission through the glass, and the massive amount of spill that we constantly encounter. The large lumenbright and lumenarc both attempt to do this. They both have their pluses and minuses from a pure design standpoint and that is a whole different post
Using a good and appropriate reflector on a 250 can easily get you more uniform light from top to bottom and more penetration (intensity at the bottom) then a 400watt with a crappy reflector
Tumbleweed
Guest
Nicely put Tony
