Optimum conditions in dwc are water temp needs to be right 65 to 70 degrees or cold as hell...lbs, lots of bubbles "boiling water" and you will never need any special products for root slime, correct ppm of nutes and understanding the best ph for the strain you are growing and knowing to let it fluctuate a lil. Room temp needs to be a temp you would feel comfortable in 18 to 12 hours a day.. lbs, also the exchange of old air with fresh air.