An
honest approach to Filtration
You
need filtration because...
The typical garden pond has an unacceptably high concentration
of fish (producing ammonia and nitrite) when compared
to lakes, rivers and other natural habitats unless a suitable filtration
system is installed. Nature achieves a balance by restricting the
number of fish in relation to the available surface area. The way
to overcome this is with an efficient filtration system. After
all, one fish per garden pond would look boring!
A
garden pond is a closed environment and there is no way for the
fish waste to leave the pond. If the waste is not filtered the
fish are left to swim in their own sewage. It is not always obvious
when a pond has a dangerously high level of toxic waste. It is
possible to have what appears to be clear water in your pond
but one in which fish will not live. It may be so full of clear
toxins that even algae is unable to live in the water. What chance
do the fish have?! Bleach is clear and yet you would not expect
your fish to live in it! Unless your filter is capable of filtering
the entire water contents of your pond approximately every two
hours it is unlikely to keep your pond in a healthy condition.
When you first stock your pond the level of filtration needed
will probably be much less than that required in later years.
Fish grow! As they grow they require more food and therefore
produce more waste! Unless you plan well ahead your filter may
not give adequate performance in the future. If your filtration
system has been running for a few years ask yourself.....
- How many
additional fish have you added to the pond?
- If they
have grown, how much larger have they grown, how much more
are they eating and how much additional waste are they producing?
This puts additional pressure on your system.
- If they
have not grown, is it because your filtration system is no
longer adequate (size DOES matter)?
- When did
you last check the efficiency of your filter?
- What are
your nitrate and ammonia levels?
Most systems
can be upgraded. This guide will show you how in an easy to
understand manner.
Pond
Volume Explained
Where
do we start?....
Pond size! First... we need to establish the size of the pond
to calculate its gallonage. Unless we get this right everything else
will be a waste of time. The size of the pond governs the amount
of water to be filtered.
How
do we calculate this?
The diagrams below show a simple way to assess the volume of
an irregular shape by breaking it down into smaller sub units.

In
this example the pond has been divided in two main sections A and
B. Measure each section in feet. All figures should be rounded
UP to the nearest whole foot. For filtration purposes you would
be better to over estimate the volume. (This only applies to filtration
calculations and NOT for medication. It is GOOD to over filter
but BAD to over medicate). The volume of each section is calculated
using length x width x depth. This gives us an answer in cubic
feet. Each cubic foot holds 6¼ gallons of water. The volumes
of the two sections (A & B) should then be added together to give
the total cubic capacity. This is multiplied by 6.25 to give the
total volume in gallons.
REMEMBER
Do not under estimate the size of your pond!

|