Small New Pond Problems
I have got a little pond, only 5ft x 4ft, and 18in deep,
I have six little koi (5in long) and eight little orfe
(2in long maximum). My pond has a filter pump going
through a UV clarifier and into a box filter, it is
quite a new pond about two months old.
My problem is the water quality is not good, I have
done numerous things to rectify it, and as I'm new to
koi keeping I'm very keen to get it right.
The pH is 8.5 the ammonia is steady at 1.2mg the
nitrite is 1.0mg and the nitrate is 50-100mg. I have
turned off the UV to give the bacteria in the filter
time to mature and have steadily added more bacteria to
the filter to help the nitrite levels reduce, I may have
over fed the fish a bit at first, but I have now reduced
feeding down to next to nothing for the last week.
I have added some pond salt to help and have been
adding Ammonia Away, this does reduce the level
temporary but it rises again slowly. The pond is made of
Railway sleepers with a pond liner inside and the fish
seem happy enough. My neighbour who has koi says I'm
worrying too much, but I know with my limited knowledge
that the levels should not be this high. I have done a
partial water change down to six inches from the bottom,
are the bacteria being affected by the Ammonia Away, and
salt, and water changes?
Never mind being addicted to koi, I'm now addicted to
testing the water! Can you help as I would like to get
the water right before it starts to affect my new little
Welcome to the world of koi keeping - and the
obligatory steep learning curve!
Your experiences are not uncommon amongst koi keepers
as all of us have had to tread carefully through the
first few months as our pond and filter matures to
support a balanced, healthy stock of fish.
There are recommended ways of accomplishing a mature
pond without encountering too many water quality
problems, but from your description, it sounds as though
you might have made a number of unfortunate errors that
are only now starting to cause you some problems.
Your pond is experiencing classic New Filter Syndrome
(NFS), which unfortunately is being compounded by the
small volume of your pond and the relatively high
As the trickle continues, the concentration of
ammonia starts to rise until the pond's water quality is
in danger of stressing your fish.
To confirm this, your tests show that you have
unacceptably high ammonia and nitrite readings as a
result of the under performing filter in relation to the
demands that your fish are putting upon it.
This is because fish excrete ammonia because it is
So, by excreting it into the pond water, your whole
pond environment inevitably turns toxic (unless it is
broken down at the same rate by bacteria).
You've been adding salt which will reduce nitrite
toxicity, but your best approach is to create a
nitrite-free pond - especially as you'll be diluting
your salt content every time you carry out a water
Once your filter has fully matured, you should not
encounter any further water quality problems (assuming
you do not overfeed or overstock your pond).
pond water fish ammonia
filter nitrite "water quality" "water change" bacteria
NFS mature experiencing "Filter Syndrome" unfortunate
encounter click to read full article