I purchased a large bag of Hydroton from major orchid distributor in Miami, Florida many years ago. It does last a long time. All the LECA pellets were very uniform in size and shape. They are round and roll everywhere, and about 25% of the darn things float no matter what I do to them. I probably did the same thing you did originally. I potted in clay pots with LECA and no S/H was considered. I did this as a test, because I'm an anal putze and tinker around too much with my plants. That includes watering too much. I figured with LECA I couldn't water too much.
Let me get back on track. I recently went to the local Hydroponics store and saw several bags of Hydroton ... BIG difference. Not only were there a large range in sizes, but they were no where near as nicely spherical as the stuff from the Miami distributor. Are there different grades and styles of the stuff?
I'm now switched to Prime Agra simply to get away from the "rolling floaters" that I can't seem to keep in the pot, particularly when I have to quick flood the pot to get good flushing action.