Water 101
The facts about the H20 in your pond
By Kelly Tunney
Ammonia levels, nutrients, oxygen, and alkalinity – the list can baffle you whether you are new to ponds, or if you have been a long time pond owner. Everyone tells you something different. Some say your pond will be okay if your pH is between 7.0 and 8.5 … some say between 6.8 and 8.0 is the optimum level for your pond. It is confusing to anyone without a degree in chemistry. Who's right and who's wrong? What is it you really need to watch when it comes to protecting the plants and aquatic creatures in your pond?
The Science Of Water
Water is not only one of the most abundant resources on earth, it also one of the most scarce. Although it covers three quarters of the Earth's surface, only three percent is fresh water, and only one percent of that is available to us for our daily water needs. No one knows more about the importance of water than pond owners. And with the droughts that many parts of the country experienced last season, water has been the topic of many discussions.
pH and Alkalinity
Let's take a moment right here and now to go back to high school chemistry and review a few things about pH levels. First of all, what are they? Well, pH is a measure of the concentration of hydrogen ions in a solution. And if you jog your brain a bit, you may remember that the scale ranges from 0 to14, where 7 is neutral. Values less than 7 are considered acidic, and values greater than 7 are basic or alkaline. On this inverted scale model, there's a 10-fold increase between each number on the scale, meaning that a pH of 4 is 10 times as acidic as a pH of 5.
According to the environmental protection agency, a pH level ranging between 6.0 and 8.5 is a good profile for any natural stream, yet time and time again, you'll see people debating levels. And each time it's different. Koi experts believe that for their fish to thrive, pH levels should not be lower than 7.0 and should remain fairly neutral. The truth is that if you are merely raising Koi as pets, your best bet is to watch their behavior to see if conditions are suitable for them.
"Ideal conditions for ponds range from 6.5 to 8.5, but below 6.5 can be too acidic for Koi," Tony Alcala, a technical service agent at Aquascape Designs, says. "You can go as high as 9.5, but could experience some problems, like excessive algae growth."
Things Change
It's important to remember that pH levels are constantly changing. They can vary significantly over a 24-hour period due to respiration and photosynthesis of the plants in the pond. So, what does that all mean? Well, in the case of respiration, the resulting carbon dioxide combines with water to form carbonic acid, which lowers the water pH. Algae utilizes carbon dioxide levels and increases pH during daylight hours. At night, photosynthesis stops and pH levels decrease. So, it is important to remember that taking a reading in the morning and a reading in the afternoon are two very separate things, so don't get excited if the numbers vary.
Which Brings Us to Ammonia
According to Dr. Eric Johnson from www.koidoc.net, ammonia is the No. 1 killer of new fish.
"Ammonia is a big problem in new systems because the bacteria that would naturally dissolve ammonia are not established," Dr. Johnson says. "As well, even in established systems, ammonia may accumulate in springtime when the water is cold but fish are eating, because filter bacteria have not emerged usefully from hibernation."
So, how do you know that there are high amounts of ammonia in your system? "Ammonia accumulations cause reddening of the skin and disability of the gills by its direct caustic effect on these surfaces," according to Dr. Johnson. "Fish suffering in water with high ammonia accumulations will isolate themselves, lie on the bottom, clamp their fins, secrete excess slime, and are much more susceptible to parasitic and bacterial infection."
Ammonia is less toxic at a pH level below 7.4, but that doesn't mean you have to worry. Ammonia doesn't start to get too toxic until you reach pH levels over 8.0, and it also depends on the rest of the elements in your system.
Oxygen Levels
Just because there's oxygen throughout our atmosphere doesn't necessarily mean that there is enough to sustain life in your pond at all times. While fish can survive without food for months, oxygen cannot be compromised – even for a few minutes. There are two times, if you aren't careful, when oxygen may be scarce for your fish … winter and summer.
In the warmer months, your pond may be the most deficient in oxygen in the early morning hours. This is because of plant photosynthesis. During the daylight hours, plants give off oxygen, and at nighttime the fish absorb that oxygen. So in the early morning hours, the oxygen is at its lowest. If you have a pump continuously re-circulating the water in your pond, however, this will not be a problem because your water will be constantly oxygenated.
In the wintertime, many pond owners choose to shut down their pond's circulation system – the very circulation system that helps oxygenates the water. Also, when ice forms over the surface of the pond, a hole must be kept open allowing built up gasses to escape. To replicate the oxygenation and keep a hole open in the ice, a supplemental pump should be set inside the pond, bubbling at the surface of the water.
A heater/deicer can also be used to keep a hole open in the ice, but never without the re-circulating pump. Deicers keep a hole open in the ice by heating the area around it when the water reaches a pre-set temperature. Remember, the heater does not oxygenate the water. In fact, in the process of heating the water, it actually uses up oxygen.
Regardless of the season, the best solution for keeping oxygen available in your pond is to have a continuously operating pump and a sufficient filtration system, like the BIOFALLS® filter, that keeps the water moving by means of a beautiful, flowing waterfall. Having the constant water flow and movement introduces more oxygen into the water.
Nutrient Levels
Nutrient levels are very important when it comes to your pond. They have a profound effect on your water clarity and how much algae you may encounter in your pond during certain weather changes. After all, nutrients are what algae feeds on in your pond, and if there are high amounts of nutrients, you're going to have a high amount of algae. That's where the bacteria comes into play. By putting beneficial bacteria into your pond and allowing it to establish itself in the system, you have something that competes with the algae for the nutrients.
So, how do you get higher nutrient levels? Well, allowing fertilizer from the grass to run off into your pond can produce an algae bloom almost instantly. And, have you ever put fertilizer tabs into your plant pocket and found a patch of string algae floating near the area soon after? That could be because some nutrients being released from the soil get into the water. That doesn't mean that you should stop fertilizing your plants though … just remember that a little string algae is no match for bacteria and that the end result – beautiful flowers and plants – is worth it.
Mulch that gets accidentally kicked into your pond, along with decaying aquatic plant material, and other organic matter that finds its way into your pond will also produce a spike in the nutrient level. You might also want to pay close attention to how much you feed your fish – un-eaten food can also contribute to excess nutrients in the pond water.
Consistency Makes Sense
The bottom line, when it comes to keeping your pond healthy and providing your aquatic life with the best possible conditions, is consistency. Any kind of dramatic change in your pond's water is shocking to the aquatic life, but if changes are made gradually, everything should be okay. Another important thing to remember is that if nothing is wrong in your pond, don't try to fix it. If your fish are exhibiting normal behavior, don't do anything to change the pond's environment … it's just not logical.
"If everything seems to balance out in your pond, and your plants and animals are healthy, there's no reason to run out to buy a pH testing kit," Alcala said. "You can't enjoy your pond if you are constantly worried about your water. Just wait for the signs before you act on anything."
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