Question About Replacement Ballast
 

I have an Aqua Medic Oceanlight pendant in need of a ballast. It is a 250 Watt DE HQI and the stock ballast is magnetic. Does anyone have any recommendations? I'm sure the plug on a different brand ballast won't fit so do replacement ballasts usually come with adapter plugs or do I have to buy them separately?

If it's a magnetic ballast you should be able to troubleshoot the problem down to the individual component, coil, capacitor and possibly ignitor if so fitted. This will eliminate the need to buy a complete new ballast. That's the beauty of magnetic ballasts, much easier to repair than electronic, most of which are completely trash once they've konked out.

Check out the following link, it should help solve the issue. There's a link near the top of the web page to a pdf "HID Ballast Troubleshooting Guide".

http://www.atlaslightingsupply.com/MHBallast.html

Some components are readily available separately, such as the capacitors, but it might be just as cost effective to get a 'kit' from the manufacturer. If required, the electrical connector should be easy to switch over, since most magnetic ballasts have straightforward connections once you open the case. Look for an ANSI number somewhere on the case or inside, should be alphanumeric starting with the letter M for metal halide magnetic ballasts. This is a standard designation and will make it very easy to match components required regardless of manufacturer. Not sure what it will be for your DE setup, possibly M80 or M138/153. I have 250watt SE lamps and they are driven by Advance M58 magnetic ballasts.

I don't have a ballast at all. I bought the pendant only, I already have two and I wanted a third. The two I am using came complete, ballasts and all but these fixtures aren't easy to come buy so I bought the pendant because it was all I could find, with the intention of buying an after market ballast. Can I use an electronic ballast even though the stock kit comes with a magnetic?

By all means you can use an electronic ballast. Just make sure that the ballast specs match the type of lamp you're trying to drive. Many of the newer electronic ballasts are capable of firing multiple types of lamp, but as I mentioned earlier, magnetic might be a good way to go with respect to repairability in the future.