I'll have to double check on the Mg reading... I'm not too concern about it for now... I do plan on doing a 20% water change today and test again after a few days... as for the Vortech's, I've seen YouTube video's of both the MP20 and MP40 on a 28g JBJ... I'm leaning towards getting, hopefully trading, for the MP40... I can't believe I'm actually liking all this techie stuff... for the longest time, I've been very basic with my set up... over the past few months, I've been upgrading my equipment and I'm glad I did... the 28g set up is by far the easiest tank to maintain in my years of reefing... LoLz... :)