Had my annual boiler service today so thought I’d share this re: previous discussion about the magna filter. The brown debris you see is what it caught from Feb ‘20 to today. Like a sludge made up of rust flakes etc. The red line is approximately how much it has caught the first year we had it(2017) , and each year it caught progressively less. so the system is far cleaner now. It will never be 100% but the first year is always the most, as it compensated for many years of not having one.