"My rink is 18' X 59'.  This is my third year and I hope to build rinks for a long time. My Son is a first year Mite and can really play. 

I use blue tarps because they are thick and use 2X8" and 2X10" for my boards. My best tip is to flood in stages. I like to add 3/8 or 1/2" to deepest areas and work my way up. I wrap my tarp under and out,
(see photo) then I have created a small "pool liner". Also, the water line
freezes to the boards and makes a great clean edge and no leaks!

This year I used sand tubes to lift my deep corner instead of adding boards when the water line got to that edge. (see photo) Put those under tarp.

Thanks for the tips and photos Tim.