1.Test silence or not, please be sure to take a good oxygen tube after the test, if you do not test directly into the gas pipe, the gas flow at the outlet will produce a sound of friction.

2.The air pump must be tested outside the cylinder, do not touch the water, the air pump must be placed above the level( with the non-return valve can be placed anywhere outside the cylinder)

3.Regularly clean or replace the oxygen tube to maintain a steady oxygen output.