I'm just over the river from St Johnsbury and I did the same thing last night. Dumped the buckets and washed tanks and we got down to 17 degrees. My trees have only been tapped about 3-4 weeks, so I'm hoping for at least some commercial.
What was the sugar content of the last good sap you collected? The last run here went from 1.3 to 1 and the previous freeze didn't bring it up.
About 750 taps on High Vac.
2.5 x 8 Intens-O-Fire
Airtech 3 hp LR Pump
Springtech Elite 500 RO
14 x 24 Timber Frame SugarHouse
16 x 22 Sap Shed w/ 1500 gal. + 700 gal. tanks www.littlehogbackfarm.com