I am going on vacation for about 18 days. My grandma is going to be at our house watching the dogs and the fish tanks. I have a couple tanks that I use fertilizers on a regular schedule. Can I skip the dosing to make it easier for my grandma? Or should I pre-measure out ferts and have her throw them in the tank on the days they need to be? There will not be a weekly water change of 50% either. Should I just turn down the lights so it is not so bright and try to put the tanks on autopilot? I need help.