I am trying to plant a tank that is 36" tall, and I do not fully grasp the concept of lumens per gallon/height..etc. It all seems a bit overly complex. If I want to purchase 2 bulbs..each 24" long for planting my tank- what shoud I look for? I am trying to grow standard anarachis, hornwort, and some grasses that I haven't fully dived into yet. help me please?