Sorry for the late reply!
Could it be feeding related? Some types of food cause skimmers to go crazy. Since you mention that it only happens once a day, this could be related. Also, check to make sure air isn't getting restricted. Take the air tube off the silencer for a little while and see if that prevents overflows. If so, the silencer could be clogged, which reduces the amount of air and proportionally increases water intake, resulting in an overflow.
Justin