I think you are putting too much water on at once.
I use to find more, quick floods to be better, as you don't get that shell ice
The 3" minimum is just to clamp down the tarp, as I fill it up I walk down the parts of the tarp that float up, and eventually it stays put.
I try not to put more than about 1 mm on at a time otherwise, depending on temperature.
You definitely can build up the thickness faster from multiple floods on the top, than relying on ice growth from underneath, as the exposed flood freezes much faster.
Very important to get it to and past the point it can be walked on, until then it is at a critical stage. Any amount of snow will sink it somewhat, and it is difficult to get off if you can't get on to shovel it. If you leave it, you might be Ok, but any amount on top will insulate what's underneath, and delay the slush layer from freezing.
It will take a while before the 3" will freeze (by then it will have another inch or so on top), and even longer for the deeper areas, but in the mean time the kids will be skating if all goes well.
In the spring it will reverse and they will skate on the floating ice. At times I will drain it somewhat from underneath by syphoning some off.
Sorry, I wasn't very clear - the backyard ice is pretty much gone, but there are several public rinks around here that keep their ice in all year long. So no, the kids can't go exactly whenever they want, but they can go any time there's public skating. Ah, but if I had an unlimited bankroll a private indoor rink would sure make my husband and kids happy!
