150 Watt HPS Conversion Bulb Question

Hey, still new to growing just a quick question to anyone with experience in conversion bulbs. Im looking for a 150 watt metal halide bulb to use in my HPS system, I don't have the biggest budget so I went and bought one of those cheapo sun systems. I do small indoor grows (about a 2' X 2' closet area) for myself and friends so it suits my needs fairly well, I don't expect a huge yield from a smaller bulb which is fine with me (more concerned about quality than quantity). So my question is would it be worth getting a conversion bulb for veg? Or would I do fine using purely the HPS? Also will the ballast be okay with something like these:

http://www.lightbulbsurplus.com/index.php?main_page=product_info&cPath=6_29_35&products_id=312

http://www.tomsgrowshop.com/index.php?page=shop.product_details&flypage=flypage-ask.tpl&product_id=2582&category_id=2&option=com_virtuemart&Itemid=86

I don't want to burn my house down haha. Any feedback is appreciated.

whats the model of sun system you bought?


JP

As far as I can tell in the box and manuel it only refers to it as: Sun System® HPS 150 Grow Light Fixture. I don't know if that helps, but this is the exact one I have:

http://www.sunlightsupply.com/hort/products.aspx?request=HORT_SS150&title=Complete Systems&type=product

The first bulb listed from lighting surplus is the right bulb. You need to match up your ANSI code from the Sun System (s55) to the bulbs ANSI code. The mogul base and bulb type should match as well. First ones good to go, use this as your reference bulb for future purchases...

Thanks Spoc, thats pretty much the answer I was looking for.