Water levels in a DWC system are very important for starting a successful grow. When planting bare root clones into a DWC system make sure that the water level is just below the root crown. And with rock-wool plants make sure to have the water level just below the cube. Having the water level too high with either method will cause over saturation of the stem. The stem needs to remain dry throughout the grow. If the stem remains saturated there is high chance of developing stem rot and the plant will have no way of delivering nutrients or water. Remember, always have an air gap between the stem and the water level.