Under ideal conditions, the FilmTec membrane removes up to 80% of nitrates. However, if your water is extremely high in nitrates and you want to remove a higher percentage of them, we are aware of one company that makes a special nitrate filter that is installed after the post-filter. Home Reverse Osmosis has not looked into the quality of this company or its products and is not recommending any company or its products. We are merely providing the name of this company as a convenience to our customers, and our customers agree to use its products at their own risk.
Mattson/Witt Precision Products, Inc.: Since they do not sell directly to the public, you'll have to ask for a distributor in your area.
If you need a housing for the filter, the price is $20 for the housing, plus shipping. (No handling fee.)