It could be hard water scales that you disturbed from the recent work you performed, according to your'e other post. Try this test take some of those particles and put them in a small bowl with some vinegar and if they bubble then that is what they are.BustedThumb said:
The other thing it could be is the dip tube in your'e water heater has disinegrated. This was a big problem on heaters manufactured somewhere between 1993-1997.With a bad dip tube you will also notice your'e hot water not staying as hot as it used too.
Also, these partilcles will partially clog a faucet and shift giving the impression that there is air in the lines, when in fact they are just obstructing the flow and making it sputter.