I use Salifert, but you're still looking at shades of pink lol! If you still have high nitrates after another test kit I'd try the Nitra guard from JL or your LFS if they carry it. Dropped my nitrates from 50+ down to 1ppm now in about a month's time. But to have nitrates in your tap, RO, and saltwater mix? I'd say the test kit is off too. Good luck.

Ok thanks will have to try another test kit and proceed from there