bulb recommendations for m58 ballast

[sowellj]

I am in the process of staring up a tank again, all sps, after a couple of years being out of the hobby. I purchased a 2 250w cebu sun fixture with 4 54 watt t5s. My intent was to run radiums. However I did not fully do my homework as the fixture comes with m58 ballasts which won't run the radiums, or Phoenix 14ks. Any recommendations would be greatly appreciated. Xm20ks maybe?

 

[toothman]

I have the same fixture, when I ran 20 k bulbs the par was not enough. Hamilton 10k bulbs to me look more like 12k and will give you more par. a crisp white/blue light. It is a great fixture, I changed to electronic ballasts and now run 400 watt radium. I guess it depends how deep your tank is and how quickly you want your acros to grow. With Electronic ballast the 400 watt 20k I get par 500 on top and 400 on bottom. With the magnetic and 10k I got 350 at the top.

 

[jda]

Hammy 10K are really nice looking on M58. Especially with actinic to help a bit with the blue. Great output and color. It is a nice bulb.