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How do I calculate my pond size? – Decorative Ponds & Water Gardens Q & A

How do I calculate my pond size?

How do I calculate my pond size? Pete – Steele, AL

If someone were to ask you how big your water garden is, how would you respond? Most pond owners have an idea of how many gallons their pond my hold or how many square feet their water feature occupies, but have you ever really measured to see how close your guesstimates comes to the actual numbers?

Knowing how large your pond is down to the square foot or the nearest gallon is not realistic nor is it, by any means, necessary. You will just want to verify that what you “think” is a 15’ x 20’ is not actually 30’ x 40’. People tend to associate size with common everyday items they see around their home. It is not uncommon to hear someone tell us that their pond is about “half of a horse trailer long” or “up to my knees deep”. This may seem like a reasonable answer at the time, but when trying to break down how many gallons are in your pond, or how many square feet of surface area we are dealing with, we, unfortunately, aren’t sure how long your trailer is or how tall you are. =) To keep everyone on the same page and make sure we are all dealing with the same units of measure, we suggest you break out a tape measure and break the pond down into feet and inches.

You may be wondering to yourself why you even need to really know how much water your pond holds or what it matters if you don’t know its surface area. Bacteria products like Nature’s Defense or Liquid Clear are added to the pond based on the number of gallons you are treating. The same holds true with algae killing products like Tetra Algae Control and even Barley Straw Extract. Other products require an estimate of the pond’s surface area for proper application. Aquatic Plant Packages and Pond Netting are examples of such products. Knowing the size of your pond can also help you determine how many fish your pond should typically hold or what size Pond Vacuum is best suited for your particular application.

Now that you know the whys of sizing your pond, let’s get down to business and measure your pond out. The easiest ponds to measure are those that are shaped as simple circles and rectangles, the more irregular the shape, the less accurate our measurements become.

Length x Width x Height

This is the formula used to find the volume of a rectangular shape. It can still be used to get you in the neighborhood if you are measuring a kidney shaped pond, the numbers you get on paper however will be slightly higher than what your pond actually consists of. Measure your pond at its longest point and then its widest point. To demonstrate, lets say the length came to 15 feet and the width 10 feet. You can then measure the depth of the pond. If it is the same depth throughout use this number in our formula. If you have a plant shelf or the depth varies, measure the maximum depth and cut it in half to create an average depth. Let’s say the pond is 4 feet at its deepest but has some shallow areas for plants. We will use half of that depth, 2 feet, for our formula. If you are just looking for surface area, multiply the length and width (15 x 10) to get 150 square feet. If you are looking to find how many gallons the pond holds then multiply the length by width by height (15 x 10 x 2) to get 300 cubic feet. A cubic foot can hold 7.48 gallons of water so to find out how much 300 cubic feet can hold just multiply the two (300 x 7.48) to get 2,244 gallons. If you are also running a waterfall take into account that there is also some water being held in the stream, use the length and width of the stream to calculate a rough volume on it as well. Just like that you now have the volume of your pond.

Easy As Pi

If your pond is round in shape we will use the formula Surface Area = Pi x R² or in other words Surface Area = 3.14 times radius times radius. The radius of your pond is simply half of the distance across. If the pond is a 10 foot circle then the radius is 5 feet. Multiply 3.14 by 5 and then multiply by 5 once more (3.14x5x5) to get 78.5 square feet of surface area. To find your volume you multiply this number by the depth and convert to gallons just like we did with the rectangular pond.

If you want to know exactly how many gallons are in your pond you can use a meter to physically measure the amount of water it takes to fill their pond using a garden hose. If you are constructing a new water garden or pondless waterfall don’t forget to take into account that some of the water from your pond will be held in the stream bed. Give yourself a little wiggle room when digging the basin pond to hold the extra water if you have to shut off the waterfall for any reason.

We have a few helpful Calculators on our site that can help you find your recommended fish capacity, select the proper pump, and if anything, play with your new found pond dimensions.

POND TALK: Now that you have a better understanding of how to measure your pond compare your results with what you originally estimated. Were you close?

How do I calculate my pond size?

Why are my koi gasping for air? – Water Garden & Features Q & A

Gasping Koi

Water Garden & Features Q & A

Q: My koi seem to be gasping for breath at the surface of my pond. Why are they doing this? – Bill in Louisiana

A: If your koi are coming to the surface of the pond to gulp for air, they’re doing more than just saying hi. They’re employing a survival strategy! Due to a lack of aeration or poor water quality, your pond’s water probably does not have enough dissolved oxygen in it for the fish to “breathe,” so they’re gasping for oxygen from the air.

This lack of sufficient oxygen can then cause the fish to stress, which then inhibits their immune systems and opens the door for parasites and disease. But you can prevent that from happening by aerating the water and keeping the water quality as crystal clear as possible.

Koi breathe by pumping water over their gills to extract dissolved oxygen from the pond water. Depending on their activity level, koi require varying amounts of oxygen. For instance, a koi’s active summer metabolism will require more oxygen; a hibernating winter metabolism will require less oxygen.

This can be a challenge during the warm summer months, when the pond’s water temperature rises. Warm water holds less dissolved oxygen, so just when the fish need it the most, it’s at a lower concentration!

To pump more oxygen into the water, you can also add plants to your pond, which naturally release oxygen into the water during the day. Your waterfall or fountain will also add oxygen to your pond. But depending on your fish load and pond size, plants and a fountain often aren’t enough – especially during the summer. That’s where an air diffuser, like the KoiAir® Water Garden Aeration Kit, can help. Powered by a silent, reliable compressor, a diffuser system will add oxygen to your pond, aerate, circulate and eliminate dead spots, keeping your pond and fish active and healthy all year long.

Because poor water quality can also cause fish to gasp for air at the pond’s surface, you should also check your filtration system, and test your ammonia and nitrite levels with a standard test kit, like the Pond Care® Master Test Kit. If your levels are high, consider adding beneficial bacteria, like Pond Logic® LiquidClear™, to kick-start your pond’s nitrogen cycle.

Once you aerate your pond and make sure your water quality is in check, your koi should stop gulping oxygen at the surface. When they do greet you at the water’s edge, it’ll be for a juicy slice of watermelon or some Pond Logic® Floating Ponstix fish food instead!

POND TALK: When you see your fish gasping for breath, what do you do?

My Koi & Goldfish Were Gasping for Air After I Treated for Algae. What Went Wrong? – Water Garden Q & A

Picture of String Algae of a Water Garden.

Q: My water garden looked like pea soup so I treated it with AlgaeFix. The product worked great although it took its toll on my fish. My koi and goldfish began gasping at the surface. I immediately did a water change and only lost one small goldfish. I have used AlgaeFix for years and never had this problem. What went wrong? – Lisa of Georgia

A: Oxygen. Oxygen. Oxygen. You must be careful when treating for algae, especially pea green water or planktonic algae. AlgaeFix along with most algaecides on the market work very quickly. When the algae die, they begin to decompose immediately, robbing oxygen from your fish.

How to reduce your chance of fish loss:

#1 – Proper Aeration: Make sure you have an abundance of aeration before you treat for algae. Waterfalls, spitters and fountains all provide aeration. Although, the best source of aeration is generally an aeration system.

#2 – If treating for string algae, remove as much by hand as possible before any treatments. In the case of Lisa’s pea green water, I would have recommend that she do a 10-20% water change approximately 24 hours before her application.

#3 – Get to the root of your problems: Generally ,excessive algae blooms are caused by one or more realistically, a combination of the following: poor filtration, TOO MANY FISH or not enough aquatic plants.

#4 – Use natural products to provide clear water: Although chemicals, when used properly, are a helpful tool they should not be your only solution. For a healthy eco-system and more consistent clear water, turn to a natural remedy such as the DefensePAC and / or Barley Straw Extract.


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