Alkalinity Up (Baking Soda) , Alkalinity Down (Sodium Bisulfate or MuriatIc Acid)

Note: When controlling Alkalinity always put the product in one spot in the deepest part of the pool or spa.   If controlling pH you will broadcast the product. This is very important to remember and your Alkalinity will be much easier to controll 

Also when bringing your Alkalinity down you must add enough acid to do the trick.  Just adding small quantities will not work.  You may add 1 or more gallons of muriatic acid to do the trick. Many pool companies are afraid to tell you that.   Don't let them try and tell you not to do it.  There is only one way and that is the right way.

Also When buying Muriatic Acid always get Hydrochloric and not sulfuric acid. Hydrochloric acid is clear or yellow and Sulfuric is reddish.  Sulfuric is not as strong and is sold in many grocery stores.  DO NOT USE IT!!!