The sediment is normal. When you use the toner you can filter it before pouring it into the tray but return it to the storage bottle. I don't understand the chemical reactions involved but your observation and experience is normal for this toner.
Originally Posted by Alan Davenport
I'm not sure that I can endorse using the toner in a stainless steel tray since there are various grades of stainless, meaning not all are non reactive. Instead I would recommend heating in a pyrex container and pouring it in to a flat bottomed plastic tray surroundef by a hot water bath in another tray. Aim for a temperature of about 105F. This toner is a hassle to use but can yield extremely rewarding results. You may wish to experiment with split toning pulling the print before the toning is complete. Also you can tone shortly in Nelson Gold toner followed by a lengthy wash which you can then follow with a toning bath of selenium toner or blue gold toner. Selenium toner will turn the print a reddish copper hue and the blue gold toner will cause a cool split tone in the print.
Tim Rudman's Master Toning handbook is an excellent reference to guide you in your toning experiments.
Good luck, have fun, and take a lot of notes,