The supply (“wet”) tank tends to get most of the moisture because moisture condenses there as the hot air from the compressor cools. To help alleviate this situation, the air dryer dries the air from the compressor before it enters the supply tank. Note: Today’s air dryer technology is so effective that a “wet” tank may not be needed anymore. In a modern Air Dryer Integrated System (ADIS), air from the air dryer goes directly into the primary and secondary service (“dry”) tanks.