I bought a previously loved Ratio Six brewer over the weekend. So far it has matched expectations and I am happy with the purchase. For reference, I also have a Technivorm, an OXO Barista Brain (the big one), and a Bonavita. Out of curiosity I tried to use a Chemex with the Ratio and realized it doesn't work. The Ratio carafe has a magnetic bottom which activates the brew cycle and turns it off when the carafe is removed (safety). I ordered a fairly strong, quarter size magnet on Amazon and that did the trick! I just place the magnet under the Chemex or any other vessel/carafe which activates the brew cycle. The stock carafe and filter holder/silicone ring seem to work best for taste and heat retention, but this hack just adds another dimension to the possibilities.