This is a really good system for filling the tank but the on/off button is awkward or not a very good quality. When you push the button to turn it on, doesn't always go on so have to push it a second or third time. Of course the lighted button does tell you when it is on, but it is VERY bright. When you push the button again to turn off the light you have to push the button a couple of times and you can never be sure you didn't accidentally turn off the machine (which I have done.) To check, I tilt my CPAP slightly to make the pump kick on to verify it is on. We are rural and lose power occasionally so never know if the machine is off or ambient light is turned off until the tank goes dry in the middle of the night (I do the tilt test every night). I would have preferred a SMALL light that stays on to let you know the machine is on at a glance bright ambient light is on.