<p><b>Notes:</b></p> <p><b>①</b>Connect the air pump to the stone. If the bubble rock produces few bubbles, please turn off the air pump and let the stone soak in the water for a few minutes, then turn it on.</p> <p><b>②</b>Check the oxygen tube regularly to make sure it is not folded, bent or leaking</p> <p><b>③</b>When the noise of pump operation increases or the output decreases, you can: clean the air inlet/remove the pump and tighten the screws/replace the diaphragm</p> <p><b>④</b>How to reduce noise: cushion air pump on towel/blanket/mouse pad/packing foam paper and fix the screws in the air pump with glue</p> <p><b>⑤</b>When the air pump has more than one air outlet,block its other exits,the only outlet will have more air</p>