I have the same unit just the 60gph deluxe hi s maxxima one with a solenoid shutoff valve and tds meter. If you read through the instrutions it says that the best temp for operation is around room temp or 70 degrees but works at lower temps also, and 60-80psi water pressure. under 60psi and the gph output is about half of what the unit is rated at.. It is also better to leave the water sit in it so that the filters do not dry out between uses as this will ruin the membraine. I do not have a flush kit eaither all that will help with is extending the filter life you still have to flush the unit manually with the kit. The solenoid shutoff valve stops the unit from running wast water automatically when it is not in use.