lose mana after 18 o'cloak trigger..help me?

hi, i am seeking for a trigger that make unit lose mana after 18 ocloack. i mean lose life 1 point per second or 10 second. can anyone make for me please?? all i know is the event is game time = 18 oclock... then i dunno how>< please help me><

Can you make it every second and if time is greater than 18 and less than 0?

Heres what you do.
Make a triggers

E - Game time equals to 18.00
C - IsItDayorNight (Boolean) equal to true
A - Set IsItDayOrNight to false

E - Game time equals to 6.00 (This stops the mana loss trigger)
C - IsItDayorNight equal to false
A - Set IsItDayOrNight to true

E - Periodic Event - Every 1 Seconds
C - IsItDayOrNight equal to false
A - (OF VALUE) Set Mana of Unit (The unit you want to lose mana) to ((Life of UNIT) - 1)

For this ((Life of UNIT) - 1), its an arithmetic.

Hope this helps.