MH Ballasts -electronic or magnetic?

[Frank]

I'm adding a 250W MH to my 75G reef and will reduce my 4 VHO to 2 VHo. The VHOs are powered by an Icecap 660. I plan to use an Ushio 10k or Iwasaki 6.5k MH bulb. I'll eventually add a second or third 250 when I upgrade the tank to a 240g. I'm trying to decide between PFO, CustomSeaLife, and Icecap MH ballasts. I like the low heat output and efficiency of the Icecap. Are there significant differences in the PAR and color output from these ballasts or am I OK making a choice based on price and efficiency?

[Chuck S]

Not to make the subject more difficult but mostly with a 65K your best staying with a magnetic for the best Rendition and PAR. Now with the 10K the Blueline is the best ballast for PAR with the HQI falling short a few points. Now with a 75Gallon tank dimensions you do realize you really need two lights over than tank not one. Just thought I would point that out. A Metal Halide is a point focal light source. It will light a 2x2 area effectively.

[Frank]

Thanks, I take it the current Icecap is not a better PAR performer than the original.

I did find some similar results elsewhere:
I found this comparison between PFO and blueline ballasts, which corroborates your message. They claimed PAR of 123.3 with the PFO vs. 90.7 with a Blueline on the same 250W Iwasaki.
http://www.carlosreef.com/bulb_comparison.htm

Also, the 2001 study below makes the same message but seems to only take into account the older Icecap model.
http://www.personal.psu.edu/faculty/s/b/sbj4/aquarium/ballast%20comparison/ballast-comparison.html

[Frank]

And yes, I know the spread is 2x2 and that I should use 2 MH on a 75G. I'm slowly implementing my upgrades as my wallet permits.

[Chuck S]

Just one observation about CarlosReef. I am not familiar with this site. The Blueline beats a PFO HQI with a 10K by a few points. The Magnetic ballast is the best all around option if you plan to change spectrums and experiment between 10000k or 6500K as it allows this play room. I tend to trust data from Sanjay and Dana Riddle over all others as they are the ones who are in the forfront of the hobby with the proper equipment to do so. The equipment to make factual studies is quite expensive and I do not know any other people other than those two who have made the financial jump to provide us such said accurate information. I understand the budget concern very well I just thought I would point out the light spread if you were not aware of it.

Now Andy from Icecap does make some nice products. The newer Icecap does not have the energy savings as the older Icecap and I got to see a working model at last years MACNA. I had a chance to talk to him about that model. It took a long time for him to complete it. I had one major concern which I expressed. It had a constant hum when it was running at MACNA so I did not know whether it had come to market too early and this problem may be fixed by now. It did light the Iwasaki very nicely but of course being a new model does not have any data to substantiate any claims.