I notice residual fluid in my bio-fluid box. Is it using up all the fluid? Have I changed the fluid too early?

Only change the bio-fluid box when the buzzer sounds. This ensures the most efficient use of the full 5 litres per box. The design of the bag and valve is engineered to provide good flow, using gravity, to match the dosing level set by the module. It is very difficult to completely drain any bag of all its fluid, therefore, we slightly overfill each bag to compensate and make sure that every customer gets the full 5 litres from each bag. Drainage wedges are also fitted to the inside of each box to ensure that a ‘V’ shape is formed under the bag whilst the bag empties to assist draining.