Saltwater Aquarium pH

 

pH (power of Hydrogen) is simply a measurement of the acidity or alkalinity of a solution. A pH of 7 is considered to be "neutral", neither acid or alkaline, while pH above 7 is alkaline or "base", and below 7 is acidic.

 

The generally accepted pH level in a basic saltwater system is between 7.6 and 8.4, but reef tanks are a more sensitive, and therefore need to be kept at the higher end of the pH scale, 8.0 to 8.4.

 

from http://saltaquarium.about.com/cs/phalkalinity/a/aa061301.htm