so today i went out and looked at my sap ladded, it was backed up about 15 ft in the lower mainline, and only about halfway up the sap ladder, had about 18 in vac above the ladder and about 12 below, i took a saddle and a length of tubing and a small valve and installed it a few feet up the mainline a few feet from the lower star of the ladder. cracked the valve open just enough that you can hear a leak if your ear is less than a foot from it, so a very minor leak, and the sap ladder is working much better and not backing up the mainline. i guess i had too tight of a system on the lower part!