Page 43 - Koi Net - On-Line Koi Magazine - Issue 70

Add carbon for growth
Since the sole reason for bacteria to dispose of
ammonia or nitrite in our ponds is in order to allow them
to assimilate carbon so that they can grow, a source of
carbon needs to be added. There will usually be some
form of carbonate in the water but the most convenient
way to ensure that there is sufficient and that it is in the
most suitable form is by adding sodium bicarbonate to
the water before starting. The exact amount isn’t
important but, as a guide, a suitable amount is 100
grams per 100 litres.
It’s advisable to keep an eye on the pH level during
the cycling process and add a little more sodium
Sodium bicarbonate can be bicarbonate if it begins to show any tendency to fall, but
bought on-line or from
supermarkets where it is the suggested amount should be plenty so that it’s
usually sold as bicarbonate unlikely to need topping up. With all this done, the
of soda or baking soda. process can begin.
The precise amount of ammonia to be added can be
calculated according to the volume of water in the bay
or dustbin. In order to do this the volume would need to
be accurately measured beforehand and due allowance
would have to be made for the volume of the media. If
this is done, the correct dose rate will be 3 ml of 10%
strength ammonia per 100 litres of water which will give
an ammonia level of 3 mg/L. Alternatively, for those who
prefer not to do the maths, there is an easy way to
provide a suitable initial dose. Simply add half a
teaspoonful of ammonia to the bay or dustbin, measure
the ammonia level this produces and add an extra
appropriate amount. The precise level isn’t important
but 3 mg/L is a suitable level.
Our two favourite biofilter bugs, the ammonia bug
(nitrosomonas) and the nitrite bug (nitrobacter) are
abundant in nature. They don’t live exclusively in an
aquatic environment, they are soil bacteria and are
blown about by the wind on specks of dust. This means
that, if the process is done in the open air, there won’t
be any need to add any bacteria to seed the maturation
because sufficient will land in the water by natural
43
means. However, it could be significantly speeded up
by adding a proprietary filter starter or a small quantity
of matured media from a trusted source that is free of
pathogens.
Test regularly
For the first week very little will happen but the
ammonia level should be checked daily. Eventually the
ammonia level will begin to fall. The nitrite level should
then be checked daily along with the ammonia level and
more ammonia added to keep the level at 3 mg/L. As
the ammonia level falls, there should be a corresponding
rise in the nitrite level for at least a week, possibly two,
and then this rising level will also begin to fall.
Ammonia is added when Dose ammonia level to 3mg/L
the ammonia level drops to
keep it at 3mg/L. Cycling is Top up ammonia as necessary
complete when ammonia 3mg/L
and nitrite levels quickly fall
to zero each time more
ammonia is added.
2mg/L
Ammonia 1mg/L
Nitrite
Nitrate
The fishless cycling will be complete when the ammonia
added one day has completely gone by the following
day leaving a near zero ammonia level and a near zero
nitrite level. If the ammonia level is vanishing daily but
the nitrite level persists, cut back on the amount of
ammonia added so that the resultant nitrite level
doesn’t become too high. As with the initial ammonia
level, there are no hard and fast rules but the nitrite level
should ideally be kept below around 5 mg/L. If this
maximum can’t be managed by reducing the amount of
45