I use the kind of lamps shown in the pic.
These need bulbs like that:
http://ebay2.ipixmedia.com/abc/M28/_EBAY_90b92a500a6a89c407c34fa515aa0224/i-1.JPG
Its important to go for the right colour temperature of the bulb. Everything between 5000 and 6000K is OK. 10000K or 3000K are not good.
For the plateds I had them buurning year round for approx 13 hours.
I always had at least one 150 W HQI plus one 70 W HQI and later I had 2 x 150 W HQI in the plateds tank.

Hiope that helps

Ingo
Image