let me explain that during the day live plants use CO2 during photosynthesis and give off oxygen oxgenating the aquarium for fish. the fish give off a small portion of Co2 adding to this co2 with do it yourself co2 makes the plants produce more oxygen during the day. most people turn the co2 of at night if im not mistaken. with plants you need some sort of plant fertilizer weather it be dry substrait, root tab, and liquid fertilizers some of the more advance planted aquarium people use a mixer of organic soil, clay,and iron. for plants you will also need a good plant light. do it yourself co2 is very easy and is great once you have met the lighting needs of the plants as well as the food source aka fertilizer. live plant will also help maintain water quality in the fact that they help in the nitrogen cycle as well. they also provide a natural place for fish to hide and live. if you are looking to breed fish i also recommened plants although they are great if this is not the case.