I have not filled the ballast with anything yet. I see where some people use sand, others use rocks or bricks. I am thinking on using sand because it will be easier to remove if needed.
I wanted the grapple since the day I bought the tractor but I was not happy with what the dealer was willing to sell--just too heavy for my D160 loader. So I researched the **** out of it and ultimately found a 195lb grapple that met my needs (I think). But then it was the barrier of hydraulics. I had the third function valve installed from day one but the fittings, length of hose, etc. were a bit intimidating. I through caution to the wind, ordered the grapple, knowing that there was a solution to any issue and I would solve it when it arrived.
Picked it up yesterday and soon discovered that the valve was stuck. This morning, I tore into the valve and fixed it (having benefit of a nice youtube video about disassembling a bidirectional valve). So I am up and running.