Topics covered: Algae, Bog, Bacteria, Filtration, Construction, Location, Lapping Liner
An aerobic bog is nature's way of cleaning up water. It consists of:
1) Slow moving water
2) Lots of surface area for Bacteria to breakdown nutrients and plant fiber.
3) Plants that survive with area that are saturated with water.
Controlling GREEN WATER is the BOG’s Job: The green pigment is the water is caused by Algae. Algae can cling to the edges of your pond on rocks or liner. Some Algae floats on the surface of the water, while others are suspended in the water. Algae only grows abundantly when there are all the following conditions are met:
1) EXCESSIVE NUTRIENTS (N,K,P,)
2) SUN LIGHT
4) WATER TEMPERATURES ABOVE 48* f
Since above items 2,3,4 are things we want in a pond only 1) EXCESSIVE NUTRIENTS (N,K,P) really need to be addressed. The obvious is Nitrogen (N) also found in Ammonia or Urea. Most of the time this is caused by excess numbers of fish in regard to how much Nitrogen gas can be vented from the water. If there are no plants to use up the Nitrogen the only way to then remove this gas is by aeration. High levels of usable Nitrogen causes plants (algae) to grow.
The next nutrient to deal with is Phosphate (K) and Potash (P) (comes from Protein breakdown (digestion)). These two are called salts they do not evaporate or leave the pond as a gas. These two salts are essential for plant growth (and algae).
For all three nutrients (N,K,P,) Bacteria is essential in the detoxification and converting the complex proteins and Urea to the usable or easily removable elements. Different Bacteria work on different complex structures. Some work in the presents of air (oxygen) aerobically and others work in the absence of air (oxygen) Anaerobic. Plants for the most part do not care if there is oxygen available or not, but Fish DO need Oxygen. So the goal is to encourage Friendly (to fish) Aerobic Bacteria, to do the work, whenever possible. The Friendly Aerobic Bacteria (FAB) need a place that has moving moisture (water), a place to cling to (lots of non-toxic Surface area), Temperatures above 46*f, and it has to be DARK (no UV light), and a constant supply of complex Nutrients. In nature one of the places where FAB's do well is in bogs and stream beds. The FAB's cling to the under sides of rocks and gravel and plant roots. The moving currents bring the complex nutrients to the FAB's and then remove the byproducts either over small falls or past plants. The bogs we recommend to clean up pond water have all the different filtration methods combined.
1)Mechanical filtration (rocks and plant roots) that screen out the large particles
2) Chemical filtration (FAB's),
3)Vegetative filtration (Plants).
Consider a location next to your pond for a Bog area. This will proved filtration for your pond.
The area should be about 1/3 the size of your pond and located uphill from your pond.
The bog filtration area can be part of a water fall or stream. Construction of the bog area can be done at a later time. Do not throw away any pieces of pond liner. Bog filtration areas provide growing areas for some of the prettiest flowers found around a pond. The pea gravel, larger rocks and plant roots provide mechanical filtration and surface area for Friendly Aerobic Bacteria.
It is not necessary to have a hill or berm for a waterfall to get the benefit of a bog filtration area.
You will need an space just higher than the surface of your pond.
A Mechanical filtration bog is just a shallow pond 6 to 9 inches deep filled with pea gravel and some larger rocks. Water is pumped in to the bog at one side and trickles out of the other side. A well-balanced Bog have Bog plants (ones that like soggy soil). These are planted in the pea gravel of the bog. Water flow through the bog is a gentle flow. The current hardly bends a leaf or moves a pebble. The slow-moving water gives the plants ample time to pick up the nutrients (converted fish poop) and convert it into plant material.
CONSTRUCTION OF THE BOG: Dish out a spot in the berm or raised area, beside your pond. Lay some of that left-over liner into this depression. The overflow of your bog should be the lowest side of your bog leading back to your pond. The other 3 sides should be at LEAST 4 inches higher than this overflow lip.
We will be seaming liner where the bog liner laps OVER the pond liner. This is done with 50 year silicone caulk or polystyrene spay foam "Great stuff (tm)" between the two liners just over the edge of the pond (on the side of the "keeper ledge") Add rock back onto the liner this will help with the bonding. Fill the bog with pea gravel up to the point it is just below or level with the overflow. Stack in rocks around the edge of the bog to cover the liner. The pipe can be hidden in the rocks.
A small water fall is built on the overflow by spraying a small line of "Great stuff (tm)" foam and placing a flat rock onto the foam. The foam can be sprayed on the liner and on the rocks to form a seal. Your entire water fall can be built using the foam instead of using concrete cement. (1 foot of water fall elevation per day) NOTE: once again the finished liner edge should point UP! The overflow spot going back into the pond, the liner points DOWN!
Turn on the pump. Plant you bog plants.. enjoy your water garden!!!
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