Cheap, but adequate, lighting for a 55 gallon would be two 40 watt, cool white, T-12 fluorescents run by a single ballast that you can get cheap at hardware stores or places like Home Depot. Make your own hood out of scrap lumber. Specialized lights and ballasts are expensive, but lights and ballasts that are manufactured in very large quantities are much cheaper.having a lighting problem. Planted tanks are way to expensive. I mean the lighting.