Related words don't necessarily have to be classified the same way: sometimes a particular form of a word is much more familiar than others. However, in the case of desalt and desalted, I can't see any striking difference in usage, Pat. However, that still leaves the question of whether they should both be common (along with desalting, presumably), or both rare.
Some quick searches of US, British and Australian newspaper indexes lead me to believe that desalinate and desalinated are used much more often than desalt and desalted. In fact, the latter words are used relatively rarely, and I'm leaning towards making desalted rare.
On this topic, the informal term desal has come to be used quite frequently in Australia in recent times, ususally to mean the same as desalination, as in "desal plant", "desal project", etc. Currently desal is not allowed in Chihuahua at all. It doesn't seem to be used much outside Australia, so maybe it isn't well-enough established as a word. Does anyone have any thoughts on desal?
