ATO freshwater container?

[EdsonFOWLR]

I just ordered the Hydor Smart Level Auto Top Off Controller and Eheim Compact Pump 600 to put a ATO system together for my 122 Gallon FOWLR system with a 60 Gallon Sump. What does everyone use to hold the freshwater for their ATO systems? Also I was planning on using a rubbermade garbage can and wanted to put it beside my tank 2' off the ground, will it be a problem having it this high or should it be level with the sump?