i filled about 5" of water to the lower end of my rink, and I am not sure how to tell when it is frozen through. It is my first rink and I don't know how to tell if it is good.

I built one of these....it has been really helpful.

http://www.backyard-hockey.com/2010/12/ ... ess-ruler/

What i ended up using for the metal was a "Wreath Hanger" and marked it with a Sharpie...Works Great!
http://www.lowes.com/pd_275496-86637-70 ... Id=3826869

The rink ruler posted above works well, but you need to get it in before the water freezes.

The non-scientific way to know if your ice is ready is to slowly transfer weight onto your slab with one foot. If the ice breaks, you're not even close. If it supports some weight but water comes up from underneath, you're not quite ready but lighter kids might be ok. I don't stand on my rink until I do this at several points, and there is no water seepage up around the edges. Non-scientific, but that's how I do it.