If it were me I would flush right away. From what I have read it takes several days for the phosphoric acid to dissolve the stones. So you are better off spreading out your dosage. Also 2 oz is extreem. I almost hemoraged on less than one oz over a few days period. Frankly it frightens me what that might do to you. Also the phosphoric acid is acidic and in that high a dosage might hurt your stomach lining. You might not need the phosphorus at all. I had immediate relief with my first flush. And It was just a basic, no frills flush.