Update. Central heating has now been running ok for the last few weeks with X800. Every few days I have been cleaning out the two magnacleans I installed. Last time was today after I left heating on timed (one hour in the morning and one hour in the evening) for the last 8 days. It collected magnetite as per the photos attached. Should I leave the X800 in for a few more weeks until it collects no more magnetite or drain and fill with inhibitor now ? Many thanks.