Mastertronic Stir bar is very noisy and jumping around?
This is an indication that there is residue in the bottom of the reaction chamber. Some test kits
reagents are thick and some are heavy and leave residue in the bottom of the chamber. This causes
the small mag stirrer to jump and make noise also you get results that are not correct.
Please refer to the "descaling procedure" in the Mastertronic Manuel for details.