Library scan refresh rate ?

Hello,
I have set up Plex on my server and use it this way:

I save a .torrent file on Resilio, it syncs the .torrent file to my server in a specific folder and the torrent client Transmission automatically processes the download. Then Transmission automatically saves the downloaded file in a specific folder indexed by Plex.

However, once downloaded, the new file does not appear in Plex on iPhone or iPad. I have to manually refresh the library scan on the server or on a computer to see it.

So I’m wondering: what is the refresh rate of the scan? Can I modify it? Or do I have to do it manually each time?

Thank you very much

Check this - https://support.plex.tv/hc/en-us/articles/200289306-Updating-vs-Refreshing-a-Library

Though I can strongly urge you to change your setup and have a look at this - https://www.filebot.net/forums/viewtopic.php?t=215

Plex does not like to scan incomplete files, it can lead to all sorts of headache. So, regardless of type of program (downloading, ripping etc) one should move the files to a folder structure which Plex scans when it is complete. The above tool and method can fix that automatically.