RE: tank placement
If your tank will cover a plug, you'll definately want at least an inch further out than a plugged in power strip so you have room to unplug it. if that made sense. otherwise the only consideration is if you would ever temporarily hang something on there like a phosban reactor temporarily. I am guessing you can do that in your sump, so i think that's pertty much your only consideration.
"Maybe in order to understand mankind, we have to look at the word itself: "Mankind". Basically, it's made up of two separate words - "mank" and "ind". What do these words mean ? It's a mystery, and that's why so is mankind." ~ Jack Handey