Wow Dave, that was a good read. Unfortunately, the links in the article for the B-Ionic references are dead ends. I did however find a good explanation here: http://www.advancedaquarist.com/issues/nov2002/chem.htm This put in to perspective what JohnO said at the top of this post. I am in region one of the chart so all a have to do is wait for it to pass through my target zone. I am not so alarmed any more. thanks for the advice and the links.