stopping the gurgling

[kjcote]

my drain line drains the overflow box faster than the water overflows into the box and the air line slows it down so that the water level can rise to a set height. i have tried raising and lowering the tube in the overflow box with no success but this worked.

[Drock169]

I have ball valves on my drains so I can against the flow so it matches the same rate at which it is returned