Plumbing

So if you haven't already stumbled upon my aquarium thread. I have a 120 gallon aquarium with no sump (just my personal choice for the setup). I have found some decent Hang On Back Skimmers but I have been toying with the idea of purchasing an External Protein Skimmer and just plumbing it my aquarium directly. However, I have no prior experience with External Protein Skimmers and I don't know what is necessary? Can I install the External Protein Skimmer on the Floor below my aquarium or do I need ...

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