in their catalogue the dilution rate is 1:100, aqua, i've used their apple fresh & never had no prob's with residues, the ph levels on both products are more or less the same. in fact for more smeller carpets i used to add a bit more, very pleasent smell i thought, the apple, mint, lavender & citrus are all listed on the same page deodorisers & their ph's are 6.5 to 6.75. as a side point though, i always run defoam through to the wastetank through me hose to cut out any chance of foaming. freshi