Reseting the Stats

Does anyone know how to modify the code below to reset the stats every 6 hours or 1 day ?

$keep_time = 60*60*24*7; // 7 days for now (TODO: admin setting)

I did try to to change the ‘7’ to ‘1’ but it doesn’t work. And I’m not a php programmer.

Thanks.

https://wordpress.org/plugins/warm-cache/