[StirCrazy]

Originally Posted by Doug

Actually I believe Radiums were designed to run on pulse starts in Europe, even though most do overdrive them with HQI ballasts. Like most overdriven bulbs though, they require more frequent changing.

the pulse start is a north american ballast created to run bulbs with out probstart built in, but it is not the same output as an european ballst so in fact the 250 watt radium is not being overdriven by a HQI ballast, also no 250 watt bulb is being overdriven.. this is a common misconception from people who claim to have 400 watt HQI ballasts, of which there is no such thing so they use a son agro which does overdrive the bulb. the M80 ballast is a European output from a north American power supply.

I also, found that the bulbs lasted longer on the M80 for two reasons, 1 they are a pulse start regulated reactor type ballast which will output a steady output over a wider range of input fluctuation so the starting is easier on the bulb (which a pulse will do also) and because the out put is more stable there are less re strikes with common power fluctuations.
Also because they are being run at voltage and currant levels for which the bulbs were actually designed they lasted longer. I ran my AB's for 2 years with only a 11% decrease in output, my radium lasted 18 months and the only reason I changed it is I had some new bulbs to try. There are a lot of myths in the hobby as to bulb replacement which for the most part are driven by the industry that makes the bulbs so they can make money off after purchase replacements. and if you look at the last 5 years there is proof, it used to be that MH bulbs only lasted 6 months and then you "had" to change them, now they are saying 12 months, nothing has changed with the bulbs, but rather people actually started doing life span testing like my self, so places had to change there recommendations to they didn't appear to be a money grab.

So in a since any 250 watt European design bulb (which is 99% of them in this hobby) is being run properly by a M80 ballast.

as for the radiums looking less purple when driven properly.. this is true, I found them way do dark on a pulse ballast as they were not being driven properly and they had low PAR out put. On a M80 ballast they were a little brighter but more blue instead of purple and pounded out a ton of PAR. you can always as purple with the addition of URI super actinic VHO if you like the purple look over the blue.

Steve