Hi,
I had those ones and could never figure them out, I found them really inaccurate because they'd say no ovulation but I'd have EWCM. I bought the more expensive ones which give you a smiley face, or a flashing smiley face and that matched the EWCM so I think they are better...although its an expensive business.
Easier said than done sometimes but if these tests stress you out just stick to having sex every two days across the week you think you'll be ovulating.
x