Ballasts and lights

ok. i currently have cfl's but i want to switch to mhl's and hps but i dont understand how lights and ballasts fit into each other. i know i need the same type of ballast as a bulb but if i buy the right ballast can i use the metal halide lights and high pressure sodium lights on the same ballast.
also what is a good wattage for growing under 5 plants using mhl's and hps. and last but definitely not least how many cfls under what wattage can match the same wattage of the previous question(i didnt mean to b so complicated in my question but it was the best way i knew how to put it)

Most of the time, you buy it all at once, bulb and ballast so thats not really a problem. You can get digital ballasts that can run both M/H and H/S and i would say they save a heck of a lot of money, on electricity and the fact that you only have to buy one; they are better for the bulb too. For growing 5 plants i would recommend a either a 250 or 400watt M/H and a 400watt H/S. To get the same u would need tons of CFLs, its not just wattage but HID bulbs give MUCH better light penetration which allows light to get to the bottom leafs. If you must go with CFL, go with some 200/250watt Envirolights, 2 or 3 ought to be the same as the HID bulbs.

Hope i helped

mzn710 said:

its not just wattage but HID bulbs give MUCH better light penetration which allows light to get to the bottom leafs.

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so what kind of HID lights should i go for

well, for 5 plants i would recommend either a 250 or a 400watt M/H for veg stage and a 400watt HPS for flowering, they are the two typical lights people use.....

mzn710 said:

For growing 5 plants i would recommend a either a 250 or 400watt M/H and a 400watt H/S.

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Light is everything, 400W is not going to do it for 5 plants. Go 600W definately, and get a cooled reflector and inline fan with the money you saved on the second ballast.

Here's a digital s/w ballast:

Regular:
NEW Digital 600 w HPS hydroponic ballast grow light kit - (eBay.ca item 360014483356 end time 16-Mar-08 14:12:44 EDT)

Air-cooled
DIGITAL 600 w HPS ballast AIR COOLED grow light KIT - (eBay.ca item 280192909413 end time 16-Mar-08 14:13:12 EDT)

You may also want to make sure you have a supplier for 600W mh bulbs in the long term. i don't think they are as common as the 250/400/1000.