Dive only salt? Lucky you! I'm eight hours away from the coast, so if I'm going to keep my skills up and get in something close to the number of dives I want (is there ever really enough of those?) then I must dive in what's available.
After checking the logbook, about a third of my entries are saltwater. The others are fresh, but I try to keep it varied. I dive springs (great vis, but shallow. However, some are rather unique), quarries (boring? Well, we try to keep things livened up with games, training sessions, etc...) and lakes (Okay, so really clear ones are hard to find. So it tests other skills, sort of like doing a night dive. That's not bad.).
Perfect? Not even close, but hey! It's underwater!