so im using an 18 gallon tub for DWC and have 4 plants . what kind of wattage lamp should i use? its about 1.5x3 Plant Max 360 Watt Plant Max MH to HPS Conversion Bulb - Style # PX-MH360LU, conversion bulbs,conversion bulb,hid conversion bulb,hps conversion bulb,mh to hps conversion bulb,high pressure sodium conversion bulb,high pressure Seems really cheap compaired to most why is this??? And also i know i need a hood for my light and a Ballast anything else i need for lighting or should be concerned about?