where are you getting this water/what salt mix are you using? When you say pre-mix, are you buying pre-made water from the store? Are you testing these levels on the brand new water, or water that's already in your aquarium? Those numbers are whack for new water, your pH should be around 8-8.2, a pH of 7 might actually be dangerous from some reef animals, I think the lowest pH naturally found in the ocean is 7.5. Also that's unnecessarily high levels of calcium, high enough that it might actually be suppressing your ability to raise alkalinity.
What are you using to try and raise alkalinity? What are your magnesium levels?
TBH, I would consider looking in to using a different source of water, or mix your own with high quality reef salt.
Also, if you haven't found it before, check out this article in Reefkeeping magazine, it's a really good primer.
http://www.reefkeeping.com/issues/2002-04/rhf/feature/