Robin, I spoke to one of the workshop hosts and he said it’s a cleaning agent, rather than a rinse agent. If the carpet is not too badly soiled, it doesn’t need a ore spray, just use f90 in the clean tank like a rinse and extract procedure, but can it be used as a rinse agent too? Would the pre spray need to be acidic rather than alkaline, if using f90 as a rinse, or does the neutral phi procedure just apply to natural fibre carpets?