150W metal Halide
 

Hi,
How deep does a 150W metal halide penetrate a saltwalter tank?
Jim

All the way to the bottom, need also to consider how deep is the tank and what do you want to grow there. Clams on a 24" probably not, some LPS sure.

18-24"

IMO,
clams and SPS should be good to about 18 inches with a 150 w

Question - When people talk about depths of MH penetration, is everyone considering just the depth of the water from the rim of the tank, or from the bottom of the light source as it sits/hangs into the tank?

As far as i know its usually the water from surface to substrate. The height of the light above the tank isnt usually factored in because its the refraction caused in the water that affects the penetration depth. Also cause its usually mounted 10" + or - a few typically.

I agree with mark and howdy about depths.

I can attest to the statement "Clams on a 24" probably not" as I can't keep clams alive no matter how hard I try and I have a 150MH with 1 x 39W T5HO and 2 x 65W PC. It needs a 250w to reach down that far successfully.