I dose Flourish iron with an Eheim Liquidoser. I put half flourish iron, and half water. Dose 5 times a day, or around 2.5ml a day of flourish. I have a 26 gal tank. No matter what I dose, my Red Sea test kit does not budge off the lowest reading. With a smaller dose, the leaves start turning yellow, so I settled on the 2.5ml/day dose. Sherlock Wong