... Air line, air hose like the air stones, is essential for any ,aquarium Koi or pond keeper Air ... line, of course, like the air stones, is essential for any ,aquarium Koi or pond keeper, and ... delivered to the point where it is required ..Air Line is very cheap and it is always useful to have some ... Airline of 1/4" - 3/8" bore size is highly recommended in all cases when supplying bottom drains which ...