what i tend to do is...
Massive water change before going
I drop my photo period to 5 hours using a timer
I set my C02 to 2 hours before tank lights on and and hour before they go off
Still dose my ferts before i go
Feed before i go
This normally works for me, however i did loose my Hygro Pinnatifida, but it wasn't well established. You shouldn't have a problem Si.