I know low tech (low light) systems are almost sacreligious here but, I've been successfully keeping low tech tanks for 22 years now. The thing to keep in mind is balance. Lighting, nutrients and CO2 all have to be in balance. If you have a high light tank, you will need to add CO2 and have a higher nutrient level available for the plants to utilize. If you don't want to add CO2, you will need to stay with a low light tank. Personally, I'm kind of old school and still use a lot of fluorescent fixtures. I've also used PC's, metal halides and VHO's. In a no CO2 system, I stick with standard fluorescents and PC's. One full length bulb per 6"of aquarium depth(front to back) is usually sufficient. So a 55 gallon with 2 full spectrum bulbs will work. Plants that are most successful in these setups are crypts, anubias, ferns, mosses, vals and some sword plants. You definately will have slower growth, but it will grow and thrive and be very low maintenance. Water changes are greatly appreciated by plants in these systems.