So I noticed that my lines were pretty inconsistent on OPK sticks and figured it must be the brands Im using -theyre both cheapies. I took both these sticks at the same time from the same sample of wee and one says Im at peak LH surge and the other is pretty faint! For the record the top stick (blue one) is Clear & Simple (ironically) retailing at 5 for a quid and the bottom (green) one is 'one step' -I think I got 30 for £3.50 on ebay which includes next day delivery! It's awful to think that someone might miss their window because of crap opk tests!