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How to Measure Your Pond for an Aeration System

How to Measure Your Pond for an Aeration System

Knowing the size of the pond is important for any pond owner. It will help determine the dosage rates for chemicals and beneficial bacteria, how many fish to stock, and which aeration system is the right size for proper aeration for your pond. Finding these numbers is not difficult, but it does require some tools, the right equation, and a little bit work. Once you know how to measure a pond, you will have a better idea of which aeration system to use.


Some numbers to know when learning how to measure a pond include the length, width, and acreage. Rectangular ponds are easiest to measure, but you can figure out these numbers for a circular, triangular, or odd-shaped pond too. Pace off (one step is about 3 feet) or use a measuring tape to get the numbers you need and them plug them into one of these formulas:

  • Square/rectangle – Calculate the length and width; L x W = surface area
  • Circle – Calculate radius (1/2 of the pond length); Pi x R2 or 3.14 x R x R = surface area
  • Triangle – Calculate the base and height; (0.5 x B) X H = surface area
  • Odd-shaped – Measure your pond in sections using the calculations above or use a handy online tool like Bing Maps.

To determine how many acres your pond is, divide your value for surface area by 43,560 (the number of square feet per acre)


Diffusers placed in deeper depths are more efficient aeration for ponds; so understanding your pond depth is important to make sure you correctly size an aeration system. If you do not know your depth or think that it may have changed over the years, it is time to familiarize yourself with the bottom of your pond. Use these tips on how to measure a pond, and start by grabbing a string marked in 1-foot intervals, a weight (like a brick), a notepad & pencil, and a boat or canoe. Then, head out to the pond and follow these directions:

  1. Securely attach the weight to one end of the string.
  2. Take your boat or canoe into the pond with your materials in hand and travel towards the center of the pond.
  3. Drop the weighted string into the pond and note where it hit bottom. Repeat in at least four other locations in the pond, more if your pond is particularly large, so that you have a good sampling to measure your pond's depth.


Something to keep in mind when learning how to measure a pond, is that ponds with an island, cove, irregular shorelines, or other unique features require more diffusers that a uniformly shaped pond as these features limit the circulation of oxygenated water. As noted above, breaking odd-shaped ponds into sections can assist you determining how many diffuser plates would be needed for the entire pond.

Putting it all Together

The folks at Airmax have done a good job simplifying the selection process for finding the right aeration system for ponds. For each of their units, they provide you with the maximum acreage a system can aerate based on the depth and a schematic to help show where the diffuser plates should be placed based on the shape of your pond.

For example – Let's consider a pond that is 1/4 acre, 13' deep, and uniformly rectangular (150' x 70'). Because the pond is deeper than 6', we will be looking at the PondSeries Aeration System. For ponds that are 13' deep, a PS10 can aerate up to 1 acre, but we still need to take shape in to account. Based on the schematics provided for each system, a PS10 is recommended for square or circular ponds, so this will not work. Instead, the PS20 will provide proper aeration for ponds of a rectangular shape.

Feeling stumped on how to find the right aeration system for your pond or have questions on calculating your pond volume? Call us at 866-766-3435 for our free personalized pond profile service, or use the Online Pond Profile Service. We'll help you to make the right aeration decision – for you and your pond!