Anyone know how to clear out the graphs without wiping the config? Thanks.
Disabling and enabling it will not clear it? I can not test it because I don’t want to loose my graphs. 
For sure, graphs are cleared when date is set back to 1970 year. For example, after reboot, when router (for some time) has no access to sntp servers it clears graphs - but I think it is not professional method.
Didn’t seem to clear them. Just came back when I re-enabled.
Do reboot for router
if Graphs still present, that is mean you are store the graph on disk
Remove store on check and reboot the router and you can enable the check later
