I have managed to source a duel bayonet 4ft LED 18watt 5700k water proof light setup up for $80. The supplier has mentioned that this set up is being used at a local Australian university in a horticultural department to grow herbs hydroponicly. Hence the reason why there so cheap the uni has ordered a ton of them. Will the duel 18 watt 5700k light spectrum be sufficient enough to penetrate a 1 and 1\2 foot tank for plant growth in a low tech tank? Any suggestions are welcomed.