I have a new 38 gal curved front tank. It came with a heater and penguin 200 filter. We also got a volcano that contains an LED light and a bubble ring so we got an air pump to go with it. I currently have it planted out pretty heavily with a variety of plants. There is quite a bit of flow in the tank from the filter and the volcano (opposite sides of tank). I'm just reading about CO2 and wondering if it's required or if I can get by with the fish and the air pump. My substrate is the eco gravel that comes tank ready with live bacteria. My pH is around 7.2-7.4, temp around 75-76 and ammonia is holding at 0. Livestock includes swordtails, glo tetras, guppies and platy. Shrimp on the way. Thoughts?