hey,well its hard for me to go with number 0.25ppm because all my liquid test are for nitrate either 5,10,20,50,110 and nitrite is read 0.1 ,0.3 ,0.8 ,1.6 ,3.3 and ammonia reads 0, 0.6, 1.2, 2.4, 4.9, 7.3 so i just go by what they read and holy i did gravel clean,and another water change in same...