I'm not a reefer, but I would have to say that is too low of watts. I think 6WPG, MAY be the minimum. I would wait for some experienced reefers to add their opinions/experiences/expertese.
I just bought a bunch of equipment forom:
drsfosterandsmith.com (they don't charge extra for weight)
thatpetplace.com (they price match)
(for base rock) I just found this place today and have contacted him about a purchase. I have not personally bought from him yet, but his base rock is about $1.90/LBs.
premiumaquatics.com (I have bought my heaters from them and am pleased)
Others can help with other site suggestions, the like.