Open the cap....
Get 2 90 degree fittings an a peice of clear tubing, put one fitting on the tpo side of the tank and to other at the bottom and make a sight gage. Like they put on coffee pots.
Get 2 90 degree fittings an a peice of clear tubing, put one fitting on the tpo side of the tank and to other at the bottom and make a sight gage. Like they put on coffee pots.