All About SkimmersALL ABOUT SKIMMERS IN BACKYARD PONDS
Nearly all ornamental fish ponds and water gardens collect or accumulate debris on their water surface. Obviously leaves and other tree materials are the most common. This surface debris left unchecked will over time accumulate on the pond floor, breakdown as organic debris through the nitrogen cycle and potentially contribute to excessive algae growth. So regular removal of these materials will contribute greatly to the overall look and health of the pond.
Skimming in smaller ponds (less than 100 sq. ft. of surface) may be accomplished with a simple "skimmer type" net and a bucket or tub. Kept in a handy location it can be grabbed anytime floating debris is spotted, or at least once or twice weekly. Skimming larger ponds this way usually means wading to reach all the floating debris.
Another option for surface debris removal is an "automatic" skimmer. These devices utilize a pump's intake to draw water into a "collecting basket or net" that is periodically emptied by the pond owner. This makes this process quicker and easier. Skimmers of this type are recommended as part of the filtration system in large fish (Koi) ponds.
Due to their size and buoyant nature they are difficult to install into existing ponds, so most are designed to install at the point of initial construction of the pond by burying the unit just outside the pond. Remember the smaller size means more frequent cleaning (emptying). Conversely the larger models will decrease maintenance frequency, but their installation requires some precision and knowledge that may go beyond the range of the typical homeowner.
Some additional facts about "automatic" Skimmers.....