A biofilter is designed to allow large concentrations of bacteria to operate effectively in a garden pond

Save money on pond pumps, pond filters, backyard waterfalls, fountains, ponds, water gardening, koi food and How to achieve crystal clear garden pond water too.

This is a 250 word (approx) summary of a chapter from my book. Each chapter or main topic has been summarised in this way. For a complete list of summaries see the right hand column

Concepts:

pond, water, bacteria, fish, waste products, biofilter, chemicals, ammonia, food, garden pond, nitrates, nitrites, conversion, poison, concentrations.

Summary:

- Generally speaking a garden pond has too many fish for its own good.

- The waste products build up in the water unless they are continuously removed.

- The waste products from the fish in their initial form are mainly expressed as ammonia which is poisonous in even small quantities and especially so under certain water conditions -- high pH -- which will be discussed later.

- Another type of bacteria also present in the biofilter then converts the nitrite chemicals into nitrate chemicals.

- These chemicals are less polluting and toxic than either ammonia or nitrites -- both of which are very poisonous.

- The health of the pond is determined by this relentless ongoing conversion of ammonia to nitrates.

- If pond water is changed frequently then to some extent the poison levels are "controlled."

- The food used has a significant impact upon the amount of waste produced.

- Waste products are converted to relatively harmless nitrates by naturally occurring bacteria.

- Rocks, submerged trees, etc all help to purify the waste products from the fish by providing holding points for the bacteria to live on.

- The more bacteria there are the better the purification.

- The bacteria need oxygen to survive and they get this from the water - oxygen is absorbed by the water due to the action of waves, waterfalls and wind.

- A biofilter is designed to allow large concentrations of bacteria to operate effectively in a small volume within a garden pond environment.

- For larger ponds the filter needs to be installed outside of the pond.