I suspect you already have medium light with the 2 bulb light, and I don't think there are any plants that require more light than that. More light might improve the color for reddish plants, if that is your goal. Adding a second one of those lights would be an awful lot of light, but if you are very experienced at getting the CO2 just right, the water circulation in the tank just right, the water surface ripple just right, and the cleanliness of the whole system just right, you might be able to use it.