Baking soda will raise your alk. I use it all the time. BUT, BUT, this is very important. DON'T just get baking soda and dump some in your tank. You need to test your tank, and see where all your levels are. Then I go to a speacial web site. post my level there and it will tell me exactly how much to add. If you add to much, too quickly. And that is anything you would use not just baking soda. You could send your tank into a presipe, episode. It usally will clear in a day, but it is very hard on your corals.