Any Par data that shows how much reflectors effect lighting?


Prolific Poster
Aug 16, 2008
Just curious if anyone has taken substrate level Par measurements of there tank, then removed the reflector and retested? I have seen Vaughn's data from his 10G with and with out a "simple reflector" and it made a big difference.

Just very curious on how much can be gained by a "perfect" reflector on a T5 or PC setup, but will take any results from any bulb type.

I'm considering going to T5HO's in the future, from my 2x ODNO shoplight and am wondering if 1 54w T5 with a TEK reflector will be enough or comparable to what I have currently.

Thanks in advance


Lifetime Charter Member
Lifetime Member
Jun 9, 2006
Some of your answers can be found here, Vaughn did a nice write up.

The T5 with a TEK reflector are nice, I use these on two tanks. I replaced a single PC setup on both tanks with 2x T5 at the same wattage for a comparison. Par reading indicate a better spread of light than the PC at the top and bottom and included more of the sides/front/back. The PC did a good job of punching light through the water column but it was fairly centered at the bottom and left the sides/front/back low. The lesson is spread out the light the best you can.

The PC's and T5's are intense and would put more light in your tank. Be aware that the will cause other parameters in your tank to change.