I am having a terrible time keeping an edge on my Glestain 210 and 240. I have no problem keeping great edges on my Tojiro DP, Kikoichi, Missono UX10, or even my Henkels Pro. A progression of 800, 1200, 2000, 4000, 8000 puts a great edge on all them, but the glestain just loses it after 15...