Co2 Is heavier than air dude so it wont do shit unless you suspend the hose ABOVE the plants. The baking soda/vinegar method is not very good. Its basically a one hit dose, which if you have ventilation means its gone instantly. You can mix 2 teaspoons of yeast and 2 cups of sugar (thereabouts) in a 2litre coke bottlle top up with water shake it up,(dissolve yeast in a bit of warm water first) drill a 1/4" hole in the lid stick your hose in and tie it above the plants. This will release c02 for a few weeks. You can use a small bottle taped to the side as an airlock/bubble chamber so you can easily see its still producing bubbles. Just put a hose from the Big bottle into the small one with the end submerged in water. Then take a hose off the top of the small chamber for your Co2 supply. They will start to smell like a brewery after a while especially without ventilation. The whole Co2 thing is a little overrated if you ask me. Shure it can help but its a weed that will grow big anyway. Just ensure they have enough freash air supply and they will have enough Co2. Hope that helps a little.