When is the best time to take an opk?

Fanistar • 2 boys ⚽️ and now a girl 🌸 My husband ( who wants an open marriage now that we had our baby 😤) and I have been TTC since late August 2017. Had a miscarriage in February 2018. Found out I was pregnant again at the end of March 2018. I'm broken but happy I

Morning or night? I know I cannot pee for 4 hours before testing. But what worked for you?