I don't want to mix cement at this time of year, so this is what I did.
Got 450 lbs of dry sand and filled up the ballast box. Hooked two 45 lbs weights on each side of the box. Then set a 180lb bag of salt on top.
129 lbs for the box, 450 lbs sand, 180 lbs weights and 80 lbs of salt is 839 lbs if I can add.
Bob