There are DOZENS of brands of protein skimmers on the market. At AquariumSumps.com we attempted to build a site that is more "elite". We wanted to offer skimmers that have passed extensive in-house testing and specialize in just those brands. Our testing includes, but is not limited to, performance, build quality, noise level, and customer service. The only brands that made it onto our site, it's because they exceeded our expectations, so we could be sure they'll exceed yours. In this case, our top four ranked brands of protein skimmer are Bubble Magus, YCA, AquaMaxx and, Nyos.
With most skimmers we carry, you will find terms such as Light and Heavy Bioloads. Light Bioload is considered a tank that is lightly stocked with minimal feeding. Heavy Bioload is a tank that is considered heavily stocked with heavier feeding. You might notice that some skimmers use a term such as "up to 700-gallons". That is what they will handle if they are lightly stocked. The heavily stocked bioload capacity will usually be around 25-40% less.