Did you mean to say you can’t get below 8 TDS?
If so, this seems like it could be the underlying problem with your high nitrates. What RO membrane are you using (GPD) and how old is it? Do you know what your incoming TDS is?
If so, this seems like it could be the underlying problem with your high nitrates. What RO membrane are you using (GPD) and how old is it? Do you know what your incoming TDS is?