I've currently had to swap out the evaporator unit for a walk in freezer which the coil had leaked on. When charging the system with refrigerant r404a does the sight glass need to stay clear at all times? The condenser is a j&e hall fusion unit model:jehr-0175-b2-l-3 , I know it may sound like a daft question but the unit cycles the condenser fan to keep head pressures regulated and when the fan speeds up the sight glass drops to half full and when the fan slows to almost stopping it clears again. Obviously I'm reluctant to just keep adding as I don't want to over charge, the head pressures have been set to cycle at 230-260psi and suction pressures are also between 16-24psi. Anyone dealt with this type of condenser before and know what the sight glass should run like?

Thanks