DO levels at 5ppm are just barely adequate for plant health. Most greenhouse crops will perform well with levels of 8ppm or higher. If DO levels drop to 4ppm or lower, the water is considered hypoxic and can be very detrimental or even fatal to the plant. If DO levels are below 0.5ppm, no plant will survive. The Watson Well ozone treatment system can produce water with more than 40ppm of DO, which in some instances is more than a 300% increase. DO at these super-saturated levels is extremely beneficial to plants.