Well, first of all yes, you can use metal halides you get at the hardware store. BUT, you need to know the color temperature of the bulbs. For reef tanks, color temperatures from about 7,000K (yellow/white) to 20,000K (blue) are ideal. Anything lower than that will be too red in spectrum, and will cause bad algae growth. So assuming you can find the proper bulbs at the hardware store, then yes it would work. But it is very difficult to find the right color bulbs. It is more realistic to find metal halide ballasts at a hardware store, and buy the bulbs from a fish store. But, you need to make sure you have the proper type of ballast, and the proper socket for the bulb. So it can be done, but make sure you know you are getting the correct items. A 700mm tall tank is about 27.5 inches. I would say 150w bulbs are not enough for anything other than soft corals and some lower light LPS. The rule of thumb is a 250w bulb for tanks 24 inches and under, and 400w bulbs for anything over 24 inches. This is assuming you want to be able to keep anything. HTH
You can use their ballasts if you are sure they are the right type (there are several high intensity lighting formats, so you have to be sure what you're getting). I wouldn't use any of the bulbs sold at hardware stores since their output quality is likely not suitable for reef aquariums.
