This is a simple siphon system. The air adjustment is controlling the amount of fluid that is drawn from the reservoir. The amount of fluid being drawn from the reservoir is affected by where the reservoir is located, it requires more air to make the draw if the reservoir is located lower than the nozzle. We also have a similar type product, DL Magnum, which has both air and liquid adjustments. Reservoir positioning will also affect the unit's delivery.
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