Hi Reefers. I am heading off for a bit of a holiday. Roughly 9 days. I was going to maintain my Alkalinity (Two Little Fishies Part B) by adding to my ATO water. Is a power head necessary you think in the ATO with alk or can I skip that. I would not think twice about that however my only available power head is an old Koralia 850 gph which is I am afraid a bit overkill for a 12 gallon rubbermade ATO. I am worried that it will get a bit messy as the water level drops towards the end of the week. My tank uses about 1/2 gallon a day of fresh water. Thoughts.