Just to play devil's advocate, but the automatic doser for adding the liquid iron into my tank fell during vacation (thankfully, didn't fall inside the tank). A week without iron showed very obvious deficiencies in my plants. My Micranthemum umbrosum turned nearly bone white at the growing tips, and my Rotala sp Green immediately started showing distorted, very pale new growth. 4 wpg.If Iron was as important as some of these people say, you couldn't get by without it. I have set up dozens of tanks for people and have NEVER dosed Iron in the water column and had plenty of success. This is not to say Iron is not important, but there are so many factors involved I don't think most people are capable of providing enough information for someone to say without a doubt what 'the problem' is. It's more of a likely suspects list at best.