Read this: I had the same prob until I added Kent Marine Tech-M, a magnesium supplement.
Originally posted by broomer5
slowest is fastest
By all means ... No offense taken and I know no harm was intended.
You make a very good point - one that has also kept me wondering. That is, what is the role that magnesium plays in our tank and waterchange water - and how does it come into play.
I believe I understand that having insufficient magnesium, less than the 1300 ppm found naturally - can prevent us from keeping our calcium levels up into the 400ppm+ range.
This I've read before - but have little direct experience.
My statement that adding just calcium will mess up your alkalinity - is true if, and only if, everything else is somewhat constant, stable and holding at a known level. I believe that this includes magnesium too.
I try to avoid using the phrase "all things being equal" that we've read so often. IMO - this phrase is one of the most dangerous presumptions we can make - because as you know - nothing is equal and everything changes in the tankwater - given enough time and load.
Your's is such a great case to mention - because it shows how a change in one - changes another. In your case - a significant drop in magnesium, allowed your calcium level to max out down around 300 - even with the reactor running. The lower magnesium level "prevented" the calcium from being saturated up in the 400+ range.
Another piece of the puzzle.
Were you able to determine what the loss of magnesium was due to ?
Did you change saltmixes or do a substantial water change, or anything else out of the ordinary, or do you think that the drop in magnesium was or is a natural occurance in our tanks ?
I'm always eager to hear of other's experiences such as yours, especially on this topic. It interests me. I certainly don't have all the answers - and like many - I am trying to learn too.
Helps us to figure it out on our own tanks - on a friendly, accessible level.