MH Bulbs???
 

How do I tell what kind of MH bulbs I need.
Sounds like a stupid question, but I have no idea what type I have..just that they are 400 watt.
How can I tell what type they are?
thanks
Neal

There should be some markings on the bulb... if not they're probably hydroponics bulbs, which CAN be used for a reef tank but not optimally. You want at least 6500K bulbs if not 10,000 up to 20,000K bulbs...

To find out what kinds of bulbs you can run, check your ballasts.

There will be some numbers on it.

M59 is a 400W probe start.
M135 is a 400W pulse-start.

Pulse start ballasts have transformer, capacitor, and ignitor.
Probe starts only have a transformer and capacitor.

Then you have to match your new bulbs to the ballasts.