Step 5: Make the hose water tight.
To make the connection water tight, take the bubble rock and connect it to the end of the hose inside the tank. Then feed the hose back into the hole. Once you feed the hose enough so the end of the bubble rock starts to enter the hole that you made, it will create a seal. Push it down so it makes a tight seal. No glue is needed so that there is no chance to contaminate the water.