Here is my 55gal dirt tank. It has a 3 bulb T5HO fixture and 4" of miricale grow organic choice dirt with a 3/8" cap. The filter is a Aqua top 404. You put 6 platys in a healthy tank and this is what you get 6 months later.
No co2 no fertz just water changes weekly "most of the time" can go with just top offs. Been up and running for 14 months.