Elite Air Curtains
Elite Air Curtains (air stones) are an effective way of increasing the dissolved oxygen in the nutrient tank. The curtain itself consists of a length of porous tube (creating minimal back-pressure on the pump), a number of ceramic weights (to anchor the tube to the base of the tank), and a cleaning ring to prevent clogging.
Air travels from an air pump, through a length of airline into the base of the tank where it is released through the air curtain as a very fine curtain of tiny bubbles. The more bubbles that a given volume of air is split into; the greater the combined surface area of the bubbles - resulting in more oxygen being dissolved into the solution.
Regular cleaning will ensure that you get years of use out of your air curtain; simply remove from the tank and run clean water over the tube whilst running the cleaning ring along its length to remove any embedded particles. To prevent solution syphoning back into your air pump do not switch off whilst air curtain is submerged.