what material for reflector

DIY! DIY! DIY! I used stainless and polished it up. Looks great! I don't think the angles are that important as long as it's angles into the tank If it's too much though then you'll get too much of a spot light effect.

 

i used aluminum flashing and use a polishing compound. its like a stick you can get it at your hardware store and use a buffing wheel. mine is like a fricking mirror. i was actually supprised that it turned out as good as it did, and then get a long 1in pvc tube as long as your reflector is and hand roll the edges up to the way you want it and it does a great job.

 

you don't want a mirror finish, you'll end up with hot spots. Otherwise you could just use mirrors.

You can get stand alone reflectors that you mount in a DIY cabinet/canopy, that's about the best way to go.

Specular Finished Aluminum is what you really want if it has to be DIY. The specular side will have a plastic film on it, don't remove till the entire thing is done. Scratches throw light around at odd angles. You'll also have to consider the angles of all your bends. A simple hood looks sort of like a rounded upside down W (as opposed to an M with straight edges) or a butt. Avoid parabolic angles, or anything that would focus the light... again you don't need to boil a little area of the tank, but rather throw light around in a controlled manner. The angles on commercial reflectors are not arbitrary, they're engineered, tweaked, and tested 10,000,000 times a minute by a computer until ideal numbers start to show up.

Mylar is aluminum sprayed on plastic, it will melt if it's within a few inches of the bulb.

Also, bright white flat enamel paint is about 95% reflective, specular aluminum is about 98%, so a good white paint will work in a pinch.

-Doug