Further maple syrup update: batch 2 was a success, but I didn't filter it and while the hippies like their food things raw and unfiltered, it displeases me to have a cloudy bottle full of niter. Attempted to filter it but it was too thick to pass through a fine enough mesh.
Batch 3 I cooked about two thirds of the way and then passed it while still very hot through a coffee filter before putting it back in the pot to finish reducing. It's now cooling but looks much cleaner.
Batch 4 is currently boiling and I'm going to filter this one twice to see if I can get it clearer still.