If incoming water hardness is greater than 10 grains (171 mg/l), it is recommended to install water softening system upstream and change the standard flow control on the drain-line to achieve recovery of the RO system at 33%, (HFRO 33% recovery kit pn-50-93201). If the particle count is >1000 counts/ml for particles less than 2 micron size, or turbidity is greater than the recommended 5 NTU limit, then it may be required to consider different prefiltration options and change the standard flow control on the drain-line to achieve recovery of the RO system at 33%. (HFRO 33% recovery kit pn-50-93201).