Been using cheapie OPKs, clearblue advanced digital, and BBT charting this month to predict ovulation. The clear blue tests have shown high fertility (not peak) yesterday AM and today AM (CD 14-15). However, the cheapie OPKs have shown an LH surge since last night (testing multiple times a day on those), so I expected today to read "peak" on the clearblue test, but it did not.