Ballast Upgrading Question

[r_quale]

Hey All,

My tank: 90 Gallons, 75 lbs (approximately?) of live rock. Currently lit by two 175watt metal halides and two 110 watt VHO's in Deluxe Captive Sun canopy purchased from Marine Depot.

The ballast is a a single-unit enclosed ballast with two switches on the front; one for the VHO's and one for the halides. Two plugs run out of the back which connect with two cords running from the fixture. One for the VHO's and one for the metal halides.

My question is, I'm thinking of upgrading to two 400 watt metal halides and, of course, don't want to purchase an entire new system.

I'm assuming there's a way to purchase just a ballast and two new 400 Watt bulbs.

However, when I'm looking around online at ballasts, I'm not quite sure what to get? And the more I look the more I'm wondering if there even IS a ballast that will work with my lights. *fingers crossed*

It seems like it goes ONE ballast per ONE metal halide bulb... But, my canopy only has one cord/plug that power both of my halides... (At least, that's what I'm assuming). So, do I need to purchase TWO 400 watt ballasts and unscrew my one enclosed unit and somehow connect wires and stuff? Or do these 400watt ballasts that I'm seeing online power two 400watt metal halides and I just need to get one and plug it in?

Suggestions/input anyone?

Thanks a lot!

Ryan
Minneapolis, MN