Recently I started testing nitrates (after my hygro started developing "burn" holes and dying off). My kit isn't 100% accurate but it does at least do one thing for sure, it tells me whether there is ANY nitrate in the water or not. Anyway, in my 32g non-co2 tank, I can add 1/4 tsp of KNO3 and two days later register 0 nitrates. That's with a full fish load too. What's up with this? Are the nitrates really being used up that fast in a non-co2 tank? Will plants take in nitrate faster if they are starved of it?