Keeping a Clear Water Garden

Many people become frustrated with their ponds with after all their hard work, they are only able to see a pool of green, and maybe the occasional frog disappear into the muck.  These are all tips that contribute to the health and balance of the water garden.

 Using Plants

  While all plants help to clean the water, some of the heavier feeders of nutrients include: water lilies, water hyacinths, water celery, pennywort, cypresses and pickerel rush.  Most ponds in full sun with no to light filtration will need to have 50-70% of the ponds surface covered with these plants.  As most water plants are vigorous, it is important to thin them out to prevent them from completely covering the surface.  Failure to do so may result in oxygen deprivation to the aquatic life below.
   
 Biological Filtration
  Biological filtration is the natural process by which ammonia, a by product of fish waste, and other nutrients are broken down through the process of beneficial bacteria.   These nutrients are then available to the plants, or released into the atmosphere in the form of nitrate gas.  Smooth pond walls have little surface area so providing substrate such as non-limestone gravel will give these bacteria a place to work.  Biological filters are canisters filled with porous media to provide additional surface area.  Keeping the water well circulated further enhances bacterial activity.

  Almost everyone’s pond turns green in the spring.  This is because the bacteria in water have gone dormant.  Since the pond has accumulated nutrients all winter, the algae is thriving and the bacteria have some catching up to do.  It is important not to change the water, but rather let nature take it’s course.  Adding beneficial bacteria products such as Ultra ClearÓ can help to speed the process up.
 
Mechanical Filtration
  Mechanical filtration is the filtration of solid particles and sludge with the aid of a sponge filter. Regular cleaning of the sponge can prevent the breakdown and release of nutrients back into water.  A sponge filter captures some algae, but most of it passes through the pores.  Adding a coagulator such as Tetra PondÓ Aqua Rem clarifier will cause the algae cells to stick together into clumps so that they may be caught with a sponge filter. 

  Water pH
   PH, which refers to the acidity or alkalinity of the water, also plays a role in algal growth.  Alkaline water makes nitrogen and phosphates more available to algae, not to mention making ammonia more toxic to fish.  Tap water around here has a pH of about 7.7, which is 7 times more alkaline than neutral water.  Ideally pond water should have a pH between 6.8-7.2.  Adding pH reducing salts to hard water will lower pH, helping to combat algae.

Fish and Scavengers
Keeping a few fish, particularly koi, can keep string algae levels down.  Some people even throw                                                    clumps of string algae in their pond to feed their koi!  Overstocking and overfeeding, however, will make matters worse.  In an average pond add 1” of goldfish or ½” of koi per square foot of surface area.  More fish may be added if a larger filtration unit is installed.  Tadpoles and snails contribute somewhat in consuming algae and leftover fish food.