Opinions on 20K SE metal halide bulbs

[Stones]

Just wondering if anyone could recommend a good 20K SE metal halide bulb to be used on a HQI ballast.

I have been running Reef Optics 20K 250 Watt for several years now but I'm sure the bulbs (or manufacturer) has changed since last year as the colour is no longer as purple/blue as the original bulbs I had. My HQI ballast also runs SE bulbs a little hotter than they are supposed to so the colour typically shifts to a lower colour temperature than bulbs should be.

If anyone knows of a SE bulb that runs quite purple/blue on a HQI ballast, I'd like to know as I'm going to have to change mine out asap. Thanks.

[fkshiu]

The XM 20K is pretty good. For the ultimate pop albeit at the cost of PAR and any longterm usage the Radium 20K is still a classic.

[StirCrazy]

the radium 250 is a sweet bulb when run on a HQI ballast.

Steve

[Stones]

The radium was the main bulb I was considering however I've read several reviews that said it didn't emit a real nice purplish colour and was actually closer to a 14K bulb than a 20K bulb. The nice thing about the Radiums is that they were meant to run on a HQI ballast.

I'm also a big fan of XM bulbs but have never tried them on a HQI ballast. Has anyone ever used the 20K XM's on a HQI before?

The last bulb I was considering was the 20K Sun Aquatics, as a review I read said that it had a deeper purple colour than did the Radium 20K. I have used their 10K in the past on my HQI ballast and it ran way too yellow for my liking, but I'm unfamiliar with their 20K bulbs.

[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.

I ran three 400,s all on BlueWave pulse starts. They were a lot brighter than running it on my normal 400w ballast but not as bright as the guys running HQI ballasts.

[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

[StirCrazy]

Originally Posted by Stones

The last bulb I was considering was the 20K Sun Aquatics, as a review I read said that it had a deeper purple color than did the Radium 20K. I have used their 10K in the past on my HQI ballast and it ran way too yellow for my liking, but I'm unfamiliar with their 20K bulbs.

I did color com parson shots of all there 250 watt bulbs, I found the 20K one lacking in PAR and almost no difference in look from there 14, which had decent PAR output. I was using there bulbs as I had a deal with the owner but he reneged on our deal and disappeared, so while there bulbs are a cost effective bulb I find the company its self rather unscrupulous and I cannot recommend them to anyone anymore.

Steve

[Stones]

Thanks for the great information. From what I've just read, it would seem that the Radium 20K's would be a better option that going with the XM's or the Sun Aquatics due to the fact that my ballast is HQI.

[Psyire]

Why not give the EVC 14k's a try? They are actually much closer to a 20K bulb yet yield more PAR.