Can I use an OPK with clomiphene

As soon as it turns positive, you can expect ovulation within 12-36 hours. Ovulation is expected 5-9 days after the last clomiphene pill.
If you start the OPK too early after the last pill of clomiphene, there is a small chance that it can cause a false positive in OPKs.
You should wait at least 3 days after the last clomiphene pill before using an OPK.