saw a video with growboss regarding ventilation in tents when he told us that it is unnecessary to have both an intake fan and extractor. He believes that exhaustion is enough. I do not want to put money on extra oxygen if I suck it out before it gives effect to the plant. how do i do to create 0 position in a 3x3 tent best so odor disappears but that my added oxygen stops and makes the effect so it does not drain in 30 seconds? Grateful for answers.