Schtoo
Derek,

Which stones might be permanently affected?

Shapton Pro? 10 minutes on #5000 and finer is what's recommended by Shapton, no more, no less. I make a habit of cleaning and drying every Pro stone I have because any moisture left on them does cause some general 'strangeness' to occur if they're not dried of any residual standing water. As I use a towel to do this, it means I must clean them first. Any kind of long term soaking will permanently and irreparably damage these stones. Glass Stones are similarly affected, and I must clean and dry them before putting them away, but no Glass Stone should be soaked for any period of time.

Chosera? 1 hour maximum is what's printed on the side of the stone. As soaking softens the stone (as it does with Shapton), any longer than this and the stone will be permanently affected, and extended soaking will severely damage them.

Sigma? I've had a report that the colourant used in the Select II 6000 may leach out if that particular stone is left wet. As the natural colour is similar to the 10000, one or the other needed something to differentiate between them and the 10000 was around first, so the 6000 got the colour.

Stu.