A buffer is a mixture of two species that keeps the pH in a narrow range. All bufferes are made up of at least two components. Baking Soda will actually lower your pH some. Bicarbonate is the more acidic of the two components, carbonate is the basic component. The pH of a bicarbonate solution is about 7. You may not notice a big change in the pH by adding baking soda but you will have depleted your buffering capacity somewhat. You want the carbonate ion in there to neutralize the CO2 (carbonic acid) being produced by your critters, especially at night. A buffer is established by creating an equilibrium between the two buffering species. In our case there is actually 3 species because of the constant production of C02 by both plants and animals.

Reefer, I make my own buffer. Try Wal-mart or HEB. Look for Arm & Hammer washing soda on the laundry aisle. I keep meaning to right up the procedure and recipe I use for making buffer to post here. If you find some let me know. I was just given some by a MAAST member and made up a 3 kg. batch. Just remember to break up the chunks so that you are able to evenly mix the two components. A cake mixer on slow speed and a large mixing bowl works good for mixing.

Drop me a note if I can be of furhter assistance.

Gary