FLA means RUNNING current! Starting current will be 3 to 6 times that, hence your 7 KW generator will notice when that sucker starts. Some of the RO units on the market that use very low power are able to do so because they recycle the high pressure. They can make water for as little as 1 amp hr. @ 12vdc per gallon!
The advice about only using RO water for flushing is very important, as chlorine WILL kill the membranes quickly. In my job I design and build RO units for wastewater. A whole lot of other issues there.
Gary H. Lucas