Gary's right about adding some calcium chloride (wait, did I just say Gary was right about something?) to bump up the Ca to 400 or thereabout. This might knock your ph and alk down a little, no biggie. Here's a link to a site that can calculate how much you need to use, and some other good info.
http://home.comcast.net/%7Ejdieck1/chem_calc3.html

Once that's done, start up the reactor, very slow effluent drip, if you're using ARM go for 6.7-6.8 effluent ph. You can also check the effluent alkalinity with a salifert kit using the low resolution (1 drop of the green reagent) it should be around 25, anything over that is great. If it's under 20, lower the ph to 6.6 and try again. Todd's also right about using the reactor to maintain levels rather than raise them. Otherwise you'll have a real see-saw.

I would keep dripping KW 24/7. Unless your ph is too high (Calfo says 8.6 in the afternoon is fine) there's no reason to stop it. If you have a high calcium demand, KW on it's own won't keep up. Another thing, it was probably the KW that saved your tank during your calcium reactor bath...if you hadn't been dripping KW and you put enough reactor effluent into your tank to send your alk as high as it got, you probably would have had a very low ph.