easi-kleen, Is your friend using the champion on wool carpets? this could be doing damage to the fibres

also if he is then extracting with a powder detergent, this should be acidic to neutralise the champion pre spray.
Regarding your using micro splitters, if you dont already have a contra rotating brush machine like a sebo duo or host , you will find your results will improve considerably, using these machines to maximise aggitation.
Paul
