I dont know about a ro system,how about a water softener first for your house needs,then fill up your tank from this, in the long run im sure this will be the better option because it has been proven to improve the life of your washing machine,washing is softer,no scum marks from the soaps u use.less wear on your system resin{it doesnt have to work overtime}and the softener will regenerate its own resin = less costs.for research type in regenerate resin in youre search the web window