MH Lighting

Keith  Breedofish at aol_com wrote:

>Hello everyone...   I just purchased a 175W MH Pendant...   Cheers....   It
>is for a 55 gallon (48x12x18) tank.  When I hooked it up and hand-held >it over the tank, I was less than impressed with it.  It seemed to only >light the center of the tank and none of the sides.  Is this common or >am I doing something wrong.  It also didn't seem as bright as my >former 80w of FLs.  I heard that the MH is much more of an intense >spotlight, while the FLs are more of a 'coverage' light.  Does anyone >else have any experience with this?  Just for note:  my entire bedroom >is lite up by the MH now, and I'm thinking about building a 'fence' >around the top of the tank to shield the rest of the room and make >looking at the tank bareable, is this feasible?

Keith,  I have been dabbling with metal halide lighting for my 150 gallon tank for the last 8 months.  Originally I purchased a 250W light system designed for hydroponic use.  I was also dissapointed by the light penetration and distribution.  So, I returned the system and ordered the 400W system.  This system put out plenty of lumens but the distribution of light was still very intense in the center and pretty poor at the ends of the tank.  Finally, I decided that you can't light a rectangular tank with a square canopy (otherwise you get lots of extraneous light in the room and poor distribution in the tank).  I am in the process of building my own system from scratch.  I bought the transformers and capacitors and have already constructed a remote ballast system for two 250W MH bulbs.  I have done all the calculations to determine light distribution from a rectangular canopy I designed.  One thing I did notice going through this process, there are rather large differences in MH bulbs.  The bulbs I purchased recently have much greater output than those which came with the hydroponic system.  With the new bulbs I may actually have more light than I need.   The color temperature of the bulbs I have now is 4200K.  Not perfect but will do just fine.

Feel free to E-Mail me if I can help you out further.

Scott Corbeil
corbels at macmail_mcgawpark.baxter.com