i have two aquaglo 18" T8 18000 k lights in my 55g. i didnt buy them to grow plants just to bring the colors out in my fish. now iv decided to get rid or the plastic plants and try and grow a few low light plants. will the lights i have grow any plants? if so what kind? i dont want a crazy planted tank just a all natural looking tank with a few live plants. do i need to have some kind of co2 system? i dont want to buy one if i dont need to. thanks