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Problem with Radium Bulb Inside Sunpod

99sf

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I have been using a 30" Sunpod on my 29 gallon open top tank at the office for about 18 months. Previously, it had 150 w DE Ushio bulbs, which worked OK. Since everyone raves about the 20K Radium bulbs, I installed one about a week ago in the Sunpod. Today, the bulb has shut off mysteriously a few times in less than two hours. I don't think this is a normal part of the bulb "burn-in" process. Can anyone suggest a solution to my problem?
 
Is the ballast a "HGI" or one that can actually drive a Radium? Not all ballasts can.
 
Gresham, I looked inside the fan opening on the Sunpod, and the sticker says the ballast is Electronic HID, 150-watt M81 M142. Is that the same as HGI? I am not a MH expert!
 
Christina the Sunpods are easy to open and check full specs on the ballast; perhaps a ballast swap for an Icecap/Hatch but if you were happy with a different bulb then ditch the Radium?
 
Sadly, Sunpods and Radiums do not work well together. The electronic ballast that is in the Sunpod is unable to consistently ignite and drive the Radium, which is specified to require an HQI ballast (as Gresham pointed out).

Most people on Reef Central find that it works for a little bit (less than two months), then never fires again.

Unfortunately, the only options are to swap out ballasts for a heavier HQI one, or go for another bulb. If you are interested, I do have an older Phoenix 14K 150W bulb you can try out on your setup to see if you like the color before you decide to buy a new one.
 
That's odd, the M81 is an HQI ballast along with the M142, but the label says electronic ballast, yet labels it with two different pulse start ballasts.... My head hurts....
 
I recall seeing this thread on Reefcentral - "150w radiums are not designed to run on anything but a a magnetic pulse start ballast rated for 150w HQI bulbs. (ANSI M81 spec ballast)."

"The bulbs REQUIRE a special ignitor, which is what a "pulse start" ballast is, it sends a powerful surge of electricity to "ignite" the bulb, it is not guaranteed to work on any ballast besides this type."
 
Yeah, Radiums are meant to be run on certain ballasts, I found the hard way; my Aquactinics fixture would only burst a small flash with a radium installed then nothing; found later about the pulse start for magnetic ballast requirement to run Radium.
 
Yes there needs to be a capacitor to ignite the bulb, or "strike" it as the case may be, but that seems to not be the problem here. Electronic ballasts are capable of firing a Radium, however, they significantly under drive the bulb which leads to an early bulb demise due to the splattering on the inside of the envelope.

A probe start ballast will not fire a Radium, or any other "HQI" bulb for that matter, in fact IIRC there's no such thing as a 150w probe start ballast, the prob in that watt range is a 175w ballast (M57). The shutting down of the ballast could be heat related. For example, if you have a very old bulb driven by a magnetic ballast, the voltage to keep the bulb ignited exceeds the normal operating voltage, that creates strain on the ballast causing it to overheat and shut down. Ever see a HID street light that goes off and on constantly? That because public works needs to change the bulb, if they don't eventually that leads to ballast failure.

Just thinking out loud, the verbage on the unit its self is rather confusing as to WTH is in there.
 
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