Metal Halide PAR question

[brandon0350]

If I have a metal halide that gives me 100 PAR at a given place will adding another halide with same bulb, ballast and reflector give me 200 PAR in that same location?

 

[Michigan Mike]

What location? What bulb/fixture/ballast/reflectors, what size tank, where did you take these readings & with what?

 

[brandon0350]

Its just a general question. Maybe its a dumb question but does adding a second halide double the PAR? I'm setting up a 60 cube and I have a 72" halide fixture w/ 3 150w bulbs. I was thinking about taking it apart and installing 2 of them in a canopy.

 

[rtparty]

In short, no. Not all bulbs, ballasts and reflectors are equal. Even from the same company.

PAR may double in some areas but not consistently and not over the whole tank.

Sent from my Galaxy S3

 

[t4zalews]

In short, no. Not all bulbs, ballasts and reflectors are equal. Even from the same company.

PAR may double in some areas but not consistently and not over the whole tank.

Sent from my Galaxy S3

I have 2 Radiums, the left one puts out ~150 more PAR than the right above the surface, but surprisingly, the are about the same when you go 12" under water.

 

[sirreal63]

Adding the second fixture will help the lower par areas on the edge of the light beam, but you will not doubling the par, you will be spreading out the light which will give better coverage. If this is a 3' tank, one MH bulb in the center will give you light in a cone shape from the bulb, where the light is a cone in the center, like this...
| / \ |
Adding the second bulb will increase the coverage and will increase the par where the beams of light overlap, like this...
| / X \ |

The par at the convergent points may be doubled but the overall par in the tank will not, however you will have much better coverage which is what you want.

 

[fishgate]

I think I understand your question and the short answer is, "Yes, PAR is cumulative".