I have a RO system for sale that just in not in use right now, not sure on what filters but from are terible water of 890 tds it gets it down to about 100. No DI on it, but has some extra 5th unknow filter (smallest one on top) which for some reason raises it too 300, so usless in are fish case. All filters LIKE NEW, so system is good for about a year befor changing. Any questions or conerns ask. Thinking about $85 or best ofter, not good at pricing things. possibly trade for somthing idk.