What Causes Low Alkalinity In Fish Tank. Baking soda is a rich source of carbon and has alkaline properties, which make it an excellent neutralizing agent. If your fish have pale coloring, are laying on the bottom, or stay close to the surface, it could also indicate that they are experiencing difficulty breathing.

Baking soda is a rich source of carbon and has alkaline properties, which make it an excellent neutralizing agent. Adding baking soda will increase the alkalinity of the fish tank water. Also, too high of alkalinity can result in the skin of fish being burnt.