All About Skimmers


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.....
  • A pump is required. A submersible pump can be placed into the skimmer container (easiest), or an "out of pond" in-line pump may be used.
  • Determine the proper size skimmer by first choosing the desired pump. Check the skimmer's recommended flowrates (based on the width of the opening or door) to match with the pump. Also be certain the skimmer is rated to the size (square feet) of the pond surface.
  • Most models are equipped with, or have the ability to add filtration "pads" or media to make them another point of pond filtration. Many models even have built-in ports for easily adding a U.V. Light.
  • Since skimmers pull water from the surface only, consideration of water movement in the bottom layer of pond water is vital to overall circulation and proper filtration. This means adding another pump on the pond floor, or additional intake or return points for flowing water.
  • Consideration must be given to "disguising" the skimmer into the pond edging. Lightweight "faux rock" covers are available to help with this.
  • Finally and most importantly...Skimmers require regular attention. Since they operate via the intake of the pump they must be checked/cleared periodically or the risk of pump damage is great. The ponds water level must also be carefully monitored to ensure that evaporation or water loss does not allow the skimmer to run out of water, which would cause pump damage. Ponds that are subject to large deciduous fall leaf drop should be covered with netting to keep the skimmer clear during this period.