Mass Coral Death

[gregzz4]

If I read your post correctly, you test after a water change
I prefer, and recommend, you test your paramaters before a WC

Personally, I like to know what's been used and other stuff before a WC so I know what is going on and what I may need to do to keep the Big 3 stable
Earlier in my venture, I also tested a day after a WC to see what was up

Testing after a WC doesn't give you enough info as it's just what you've changed now, not what's been going on in between the changes

Maybe others have different opinions, but, when I'm adding New Salt Water with readings of 10-11 Alk, 450 Ca and 1400-1450 Mag to my system, it makes a difference to me how much and how often I do WCs

Changing 15% bi-weekly is very different for me than when I do 10% weekly
This is because of my NSW content

Hope this makes sense, I'm tired and off to bed