I want to extend the tubing slightly on my Fluval 405. Just on the part where the outlet goes into the water. A few days after a water change, once a few millimetres of water has evaporated, the sound of the water outlet drives my husband nuts, so I need to put the outlet under the surface of the water (and I have bought another pump for another water stone to compensate for the loss of oxygen). Where can I buy some more tubing and a little joiner thing?