I just switched salt mixes - I had been using Instant Ocean, but was finding my calcium and magnesium levels too low. So I bought some Seachem Reef Salt, and did a 25% water change. My calcium is now at 460 (had been at 400), but I was most surprised by my magnesium. It used to be around 1100. Today I ran a Red Sea Mg test, and it was off the scale (although the scale ends at 1300). I kept adding reagent, and would estimate the Mg level at around 1600. So.....what do I do? Are levels like this detrimental to the tank? Is this significant? Advice, please.