I have the Oneida V-3000 system and the 35 gallon drum... I have found that the red light/sensor that tells you when the drum is full is not reliable... Not sure if it's a bad connection or just poor sensor, but I'm wondering if anyone has tried to modify the drum so you could actually see how full it is? Would cutting a small hole and then sealing it with say 1/4 inch thick plexiglass work?? Just trying to find a simple, low-tech way to monitor how full the drum is getting, without disconnecting it etc.... Thanks for all ideas!