I agree that there are not many specific texts that deal with water chemistry as applicable to fishkeeping. As someone with a background in chemistry (I have a B.Sc and have worked in the enviromental chemistry field) my suggestion is to get hold of a general introductory text on chemistry. The sections of interest are aqueous and/or inorganic chemistry. This should have an introduction on the principles of solubility, pH and buffering. It is difficult however to apply many of the equations of analytical chemistry since these are based on systems containing a few pure components, and are only loosely transferable to real systems, where literally dozens of chemical compounds are combined. The principles are more easily transferable, and whilst you won't get hard and fast numbers, they will give you an indication of what to expect. The whole issue is confused even further by aquarists using terms (such as hardness) that owe more to the results an easily performed test than any specific chemical property. I will say that understanding the chemistry of the water we use is something that goes a long way to helping us offer the best possible environment for our fishes, and hence increases our successes. Steve