Well, it's not a bad idea to hover in the 10-11 dKH range for awhile considering how long you figure it was high for. If you feel like experimenting after a few weeks, you may find your corals are even fuzzier if you drop the KH down further. Mine definitely show best polyp extension in the 7s. I can tell by looking at my corals if my KH is out of the happy range. My corals don't seem to show any immediate signs when calcium is out of range though...I wish they did!!
Well, you're just going to have to add the calcium and see where your alkalinity ends up. Adding 50 ppm calcium will definitely drop the alkalinity further. However, if you add say 30 ppm to bring you to 410, and that drops your alkalinity to 7 dKH don't add more calcium - these are balanced numbers. Just wait a few days to see if your reactors will raise cal and alk on their own, or you may have to turn your reactor up a tad. Just remember that you want to
balance the numbers at this point, then mess with the reactor which will raise/lower
both cal and alk at the same rate keeping it balanced to whichever level you want to get to. Messing with reactors is way easier to explain in person/on phone.
