Thanks for that link Aeros. Very informative. I thought I had gone through every AA and RK article since their inception but the one you linked to didn't sound familiar to me. Either I read it really early on in my reefing days and didn't understand it, or missed it, but today that is a treasure trove of good information on that subject (heavy metals in the aquaria).
Can anyone explain to me how a CA reactor can raise alk so high it crashes a tank, but still leave calcium levels a little lacking? I have a friend with a 240G tank and 6 months ago he switched from dosing to a CA reactor, worked great for 5 months. pH is set right on the effluent. CA last week was 360 and Alk was over 14 and all his SPS corals died. He went from an Alk of 5 to over 14 in less than a week, didn't make any changes at all to his system, all of the sudden he got a huge alk spike. I have no clue how to to explain it (I admit, I have never used or setup a CA reactor myself, only seen them in action on other peoples tanks), which is why I am asking the question.