Small ponds live life similar to their larger cousins, only magnified. Water quality can deteriorate much more quickly in small ones. Temperatures rise and fall faster in small ponds than bigger, deeper lakes. With that in mind, always remember, “Water is as water does.” Forrest Gump’s cousin Gabby said that.
Water is the medium. Everything that can dissolve into water, will. Remember that. For example, pond bottom soils have lots of limestone and iron. Both those minerals will dissolve into water until saturated. Tree leaves fall into the water. You have stirred those shallow soils and seen black, mucky, stinky junk boil to the surface. Smells like rotten eggs. Water is slowly processing organic matter, allowing it to decompose and break known to fundamental nutrients. Those nutrients are reused, maybe as aquatic plants, maybe as plankton… or maybe simply stored in silty, gooey mud, to be used later.
As resilient as water is, don’t be lulled into thinking it will respond as you wish. Water has natural limits. Push those limits and Nature pushes back. Since water is the medium, don’t blame it when things go wrong. Think about it this way… different nutrients, minerals, and metals dissolved into water always will be a stimulus for a natural reaction. Always. Add sunlight and temperature to water loaded with nutrients and something will grow. If we manage things properly, nutrients and their mineral cousins lend themselves to the genesis of a food web. That is, nutrients feed microscopic plants, which feed microscopic insects, which feed larger organisms, and on up the food chain to top predators such as fish.
But, if one link of the food chain is pressured, the remaining chain responds. For example, add too many filter feeder critters into a system, and zooplankton drops. Then, big algal blooms take over and the rest of the food chain suffers. Add too many predators at the top, and the middle food chain disappears.
Okay, enough biology stuff. What does it all mean to you? The older a pond, the more attention it typically needs. Keep your mini-pond young by moving the water. Keep the water moving and you expedite all natural processes we hope are occurring. How do you move water? The least expensive, artificial way is aeration. Create vertical currents top to bottom. Use low pressure, high volume aeration systems to expose as much pond water to air as possible. Contacting water with air speeds things immensely.
Another way is to move water. It’s common to see mini-ponds with electric pumps drawing water from deepest areas, pushing it uphill to a wetlands-style bog, then letting it descend along a small scenic waterfall, and splash into the pond. Creating a natural filtering system through a bog allows landscaping plants to cleanse the water as it moves back home. Such ponds allow the manager to push the envelope of fish production while enjoying ambience of clean, fresh water.
Moving water allows Nature to do what it does best–clean house.