I got a "7 Stage 150 gpd RO+DI+UV Reverse Osmosis Water Filter System - Aquarium" from ebay. It's overkill for the garden having DI and UV. I wouldn't buy into that again. h20splash is the company there and they have an infinite combination of systems. I'd keep it simple next time. This one adds minerals I believe and i really don't want that. I'm waiting for them to wane away. Actually when the membrane needs replacement I'm going to see if I can remove the minerals when it's apart.A lot of RO units advertise the ability to filter water at higher concentrations of TDS without significant degradation of the RO membrane filter system. Which RO manufacture's unit are you using? I may give an RO unit a try. Bottled water is expensive.