Reef Octopus eSsence S-130 Protein SkimmerThe very eSsence of Filtration The Reef Octopus eSsence S 130 Protein Skimmer was designed for the modern day aquarist in mind. This remarkably compact in sump protein skimmer is capable of skimming aquariums up to 160 gallons where sump space may be limited. Bioload Handling The bioload of an aquarium refers to its ability to process waste in proportion to tank volume. Protein skimmers work best when properly matched with the bioload of the system.