Hello all. First time posting so please be kind! I bought the Eheim oxygen diffuser recently. I wanted to add air to the tank from the output of my 2215 Eheim. After a simple assembly I put it on the return line but no bubbles. Valve is open, all seems ok. Then I thoght that maybe this devise is meant to be even with the surface, or above, splashing into the water? Is this correct? I thought it would work submerged like the power head units do. Any input would be appreciated. Thanks.
