The only way to remove nitrates is by changing water, 50 ppm? A 50% wc will get you to 25 ppm, another will get you to 12.5ppm. Prime will temporarily detoxify amm and trites..
API liquid test is just fine, just re-read the directions, the trate test is an epic pita
That's debate able, there are products out there said to specifically aid in the removal of nitrates.. I'm a firm believer in clean gravel, filter and 50% weekly wc! Do you vac gravel often??
That seems about right, they're not do much additives.. More so filter media... You could try adding done nitrate loving plants like anarchis or hornwort..
API liquid test is just fine, just re-read the directions, the trate test is an epic pita
Is you tank as new? Whys your stock? Size?