Just found this on a website as was confused my self:
Unlike pregnancy tests, morning (first morning urine) is not the best time to collect samples for ovulation tests, as LH is synthesized in your body early in the morning and will not appear in your urine until the afternoon. The ideal time to test is in the afternoon, around 2pm, though testing may safely take place from 10am to early evening.
Should I take the test the same time every day?
Yes, be sure to test at the same time each day. Also, reduce your liquid intake around 2 hours before testing as a diluted liquid sample can prevent or hinder LH detection.
Can clomid interfere with test results or cause false positives?
Clomid may cause false positives if you test for ovulation too early in your cycle. Please consult with your doctor about how to use OPKs in conjunction with Clomid - or other fertility and prescription drugs.
The website I got this from is:
http://www.ovulation-calculator.com