Tvheadend

I have TVHeadend set to scan the IPTV network every 12 hours for new/updated channels. Previously, it was set to every 60 minutes, but as TVH has to scan 6,000 channels it would effectively stop responding whilst updating the M3U channel list, even though startup scan and background scan is disabled. Can this process be made more efficient or set to run as a lower priority? The Web Interface becomes inaccessible for short periods of 10 to 15 minutes and clients cannot connect to the service until the scan has completed.