[krackersmom2]

You're fine with a 27. I think our friend was just trying to tell you to go as big as possible so you don't have to upgrade again

You can find plastic shower caddies at Wal Mart with the bathroom hardwares (plumming), not with the towels and decor. Try to get the ones that have big plastic suction cups. When you put it in the tank, make sure to wipe away any sand grains from the glass or it won't stick well.
You can find corner caddies and I found an oval shaped one that fit nicely across the back of my smaller 10 gallon.