I use hannah and redsea for alk. Red sea and elos for calc, nyos and red sea for mag, nyos and red sea for nitrate. Elos and hannah for phosphate. Hannah for phosphorous. Salifert for potassium .All the test including salifert( i have them also) were all off by ALOT so i dont kno who to trust , red sea is my backup, as everything else listed above were the closest to my triton test