first off id take some water into your closest lfs
and have them verify the test. just because its new and its safalert doesnt mean its 100% accurate. maybe the api is correct and the safalert is off. as for dealing with your nitrates, you absolutely have to do weekly water changes. no if's and's or but's. i would personally do 2-50% water changes over the course of a week. thatll get you back down around 25 ppm
for trates. once you get a handle on that, id start looking for the root cause of your high trates. aas tone said, it could be overfeeeding, inconsistant water changes, dead spots in the water flow, etc.