I just fed the tank and went to feed C, like I do every day. I noticed my left Tunze was still on, it's not oscillating just a steady on about 30%. So I went to the status screen and manually turned off it is still on, I power cycled the Apex and manually turned off but is still on. It's only the left Tunze that will not turn off and in auto operates correctly oscillating opposite the right Tunze. Any ideas?