Although a clear water garden is possible without the use of a pump or filtration system if the pond is kept clean, the number of fish is kept within the recommended stocking rate, and the pond has enough submerged grasses, most water gardens use recalculating water. With the growing popularity of water gardening, many new pump and filtration developments are appearing in the market place.  Most notable, perhaps is the almost exclusive use of submersible pumps, now manufactured in black to blend into the bottom of the pond against a black liner.

In the past, many pump housings were made of aluminum alloys.  Because aluminum oxidizes in pond water, such pumps need a sacrificial anode attached to the pump. The anode oxidizes first, so it, rather then an expensive pump, is replaced. Stainless steel, brass or plastic housing will not oxidize in pond water.  The only oxidation precaution with these pumps is to not use two dissimilar metals in close proximity within the pond; the softer metal will oxidize.

Even though many authorities still recommend turning pond water over within a specific time-frame, a clean ecologically-balanced pond does not require rigid management.  Except in very small ponds, water flow can be based on the requirements of the water feature.

There are many ways to pump and filter your pond water to keep it clean.  One way is to use an electric pump (only a certified electrician should install this, and go over how it should work.) There is also the surface skimming technique.   This involves promoting clear water by preventing floating organic matter from dirtying the water. 

Bio-filtration makes use of nitrifying bacteria to change organic wastes and ammonia into nitrite and then into nitrates.  Since the bacteria need moving water and oxygen to survive, it is necessary to use a water feature, and/or a natural filtration system.  Preformed natural filter containers allow the water to flow from them.  The natural filters can be set up with plants to naturally filter the recycled pond water.