http://www.cichlidforum.com/articles/cycling.php
Articles that this forum lists in the beginning section. The graphic in this article shows a nitrate level of over 50 before the water change is done. I believe on the test strips list 20-40 as "normal" - though I haven't used them since getting the liquid testers, but will check tonight.
My water with weekly water changes is 10-20 nitrate with nitrite and ammonia 0. Nitrates should never be 0. Hmmm, after doing a bit more reading it looks like 10-20 is a better number to go by. Someone please, correct me if I am wrong.