If you use Clearblue digital ovulation test with dual hormone indicator to find your ovulation, this is perfectly fine, but please keep the following information in mind:
When Clearblue's test detects a rise in your level of estrogen it displays 'High Fertility' (flashing smiley face) and will continue to display 'High Fertility' in the following days while it looks for your LH surge. When your LH surge is detected, the test displays 'Peak Fertility' (static smiley face).
The estrogen is already accounted for by Natural Cycles, as you measure your temperature each day. A peak in estrogen is visible directly in the app, as your temperature drops a little bit. Only enter the 'Peak Fertility' (static smiley face) into the app as a positive LH-result. The 'High Fertility' days can be added as a comment in the Notes section for you to keep track of those days as well, should you want to.