The Wal Mart Equate tests are totally different in Canada than in the USA. Ours are the blue dye +/- tests (actually made by the same company, Inverness Medical, that makes the generic tests for CVS, Rite Aid, Target etc down in the states). Just an fyi, as it gets so confusing for us canadians asking for advice on the Walmart tests, most people don't realize they are different up here.
To the OP, yes the Canadian Wal Mart One Step tests you are talking about have HORRIBLE evaps sometimes. I don't think I have ever taken one without it looking positive, when I definitely was not pg. And the evap lines for me often showed up within the time limit, or right at the time limit cut off
: which made it even more confusing. The evap lines are blue, and often thick, sometimes dark, sometimes light, but they have always been noticible for me. It sucks. I refuse to buy them anymore. From what I have read about them on various different message boards, is that really you can only trust them as a true BFP if the line shows up immediately, like before the control line. If the line takes time to develop, even 8-9 minutes fore example, you're better off not to trust it and test again with a different brand.
Shoppers Drug Mart brand, Exact (Superstore, Loblaws etc) all detect low levels as well, apparently 25 miu's, and those are pink dye | | tests, not +/-, that might be a better option. I don't think we have a pink +/- test up here in Canada (if we do, someone please let me know!