It's just easier and less of a hassle to use scripts with DNS. There are plenty of good ones out there you just need to look for them.
Such as: Near Fantastica's DNS or Deke's DNS. You are able to set the tint screen on the basis of intervals (5), set the second, minute, hour, day, month...ect and the only thing needed to activate it is a little (*) within the map name...without the () of course.