try baked baking soda to raise alk. (sodium bicarbonate anhydroxide)
spread a thin (1/4" layer) of baking soda on a cookie sheet lined with tinfoil. Bake it in the oven at 400F for 2 hours. This drives the co2 out of the baking soda so that idoesn't lower your pH when you add it into the tank. It's ok to cook it at a higher temperature or for longer if you want to be sure.
Then use this calculator here to find out how much to add.
http://reef.diesyst.com/flashcalc/flashcalc.html
Tell it all your levels, your desired level of the parameter you want changed and what you're using to raise it. It'll tell you how much to add to raise your alk, and tell you the ballanced calcium for that alkalinity level.
For instance you have an alk of 7dkH, and you want 8.5dkH. You're using baked baking soda. Your total water volume is 100 gallons. You need to add 10.7 grams of the baked baking soda and your ballanced calcium level would be 420ppm.
(alk dosing should be done gradually to prevent pH spikes. Don't raise your pH more than 0.2 per day)
You'll have to keep on top of your dosing of 2 part afterwards otherwise your levels will just go outa whack again.
And here's an excellent article on making your own 2 part:
http://reefkeeping.com/issues/2006-02/rhf/index.php