Vaughn said it is half of what he uses. Since this a new set up the plants are under stress as is. Thanks http://www.barrreport.com/you-new-aquatic-plants-start-here/5576-will-work-my-45g.html I just read the post on weekly dosing. I have so much trouble the chem side of this. I know its Max limit that won't limit growth. So should I start with a regular EI dose for my tank or what.