I have been using this recipe by Randy Holmes-Farley for about 2 months now with very good results. I thought I would pass it along to all of you as well.
http://www.reefkeeping.com/issues/2006-02/rhf/index.php
It is much cheaper then buying pre-made two part solutions. I bought a 5 pond bag of the baking soda at Costco for less then 6 bucks. Thats will due probably 20 gallons of alkalinity solution.
It is a good time to stock up on the calcium ingredents since most of used for driveway melts. I have been using the Kent Turbo Calcium but I will be buying a can of the Prestone Driveway Melt, 8 pounds for $8, vs 1 pound for $12, the next time I'm in Home Depot.
I have not been doing the Magnesium part yet since I do not have a test kit at this point.
I make a gallon at a time of each and then fill 1 litter bottle to keep near the tank. I made a simple little DIY drip system over the sump so each night I pour equal amounts in and move on. I can post a pic if anyone wants to see.