Magnesium (Mg) is a key factor in the waters ability to maintain a balanced Ca / Alk level. Low readings (below 1100ppm) will contribute to a difficulty in sustaining stable levels of Alk and Ca, which can cause a drop in one or the other. Levels of 1350-1450ppm are ideal.
Corals use Mg at a fairly slow rate but this depletion should be the first thing tested for in the event of an imbalance where Ca/Alk is concerned.
Usually water changes will suffice in keeping levels up, however heavily stocked systems should be monitored regularly, with a possible small dose of additive when needed.
Again Hipkiss states that a low salinity reading will cause Mg test to read low
In my case the Mg levels dropped and my Alk levels went up and my calcium dropped but my Ph was stable at 8.2 all this because I slacked in my water changes and ran out of Mg.
I have no excuse other than not wanting to do anything after my father passed away, but this is no reason to slack for I know my father would have kicked my A$$ for not maintaining my system. I thank my friends in TCRC for waking me up at the aug meeting. But this is all for another topic.
