Oreo

I've got a 70gal tank I dosed 2g of dry KNO3 which should have yielded 5ppm in the tank (when considering already present nitrates.) When I tested the water about four hours later it was as if all the KNO3 I added had been used already or something.

Can plants take in over 2g of KNO3 in only several hours? (They had been kept in very low nitrate environment for several weeks. I have been dosing Excel & a liquid trace mix till today when I finally switched to dry ferts.

I've been using a very nice Hach DR2000 spectrophotometer to get precise measurements of the nutrient levels in the tank water.

Anyway, I dosed another 5g of KNO3 to get the level up. I'll test again in the morning.