Yes, occasionally I use Arm & Hammer to raise the alkalinity in my tank.
This is my little formula I use with my 20 gallon:
add 1 teaspoon baking soda to raise Alk by 1 meq/l for every 10-15 gallons.
Remember, this is just a formula that works for me.
Every tank is different so use with caution. I usually add about 1-2 teaspoons if my Alk is around 2 meq/l to raise it up to the normal level of 4. I fill a small tupperware container with saltwater from the tank and dissolve the baking soda before pouring it into a high flow area. Sometimes I break it into smaller amounts in order to not dose all at the same time.
This link might be useful:
http://www.kademani.com/reefchem.htm I would initally start with a smaller amount then you think you need then test and see where you're at. Add more if needed. You do not want to overdose. Some people also add washing soda in the ratio of 6:1 bs/ws to produce a pH of 8.0. I've done this but don't really worry about it anymore. Here is another link:
http://www.hawkfish.org/infoctr/homebuffer.htm Check your Ca too because more than likely, you will need to add some turbo calcium soon as well. I try to maintain a Ca of 440 and Alk of 4. Its truely a balancing act that I have to admit I still haven't completely mastered.
:jacko: