Background: I know you're not supposed to dig a really wide hole for a fence post hole. But the previous owner of my home did not know that. He or she dug a really wide hole, filled it with a bunch of pavers and other junk, and poured a really big piece of concrete.
The fence post broke last month and I'm finally getting around to fixing it. So I dug out all the concrete and am using a tube to make it a little more manageable.
Question: What do I fill around the cylinder form? Dirt or gravel? I'm afraid that if I use dirt, it won't be compact enough and won't offer enough support. Or maybe I should use sand or something. I don't know.
Note: I was able to get about 8 inches deeper than the previous owner into really solid ground, so the form is stuck in there very tightly. Also, this will be for a metal fence post.