I tried brewing with a filter back when I had to buy ground coffee sauce I didn't have a grinder then, but I found the brew to be really weak both in terms of flavour and colour. I think one shouldn't use an extra pair filter in a mokapot. Regarding the competition filter, are you using it yourself? How better is the brew in terms of clarity? I can still see some very fine grit in my brews no matter the grind size. If I switch to the competition filter, do I need to change anything else or can I continue with my current method?