This two-part article describes a simple way to maintain healthy water conditions in show tanks and other short-term holding facilities.


by John Egan, Port Talbot A.S.

Two chemical filtration products were evaluated during last year's Festival of Fishkeeping at Bracklesham Bay. These were Nitra-Zorb and Ammo-Chips®
whose product information below is taken from the manufacturer's information leaflets:

· Nitra-Zorb

This is composed of natural and synthetic ion-exchange resins, conveniently packaged in pouch form.
Nitra-Zorb continually removes ammonia, nitrite and nitrate from the water.

The product can be fully recharged about 4 to 8 times: immerse the pouch
for 2 hours in a warm salt solution (see manufacturer's instructions for recharging details).
For freshwater systems only.

· Ammo-Chips®

This product is composed of an
ammonia-removing resin, formulated
as large granules ("chips").
Ammo-Chips® can normally be recharged 4 to 8 times.
For freshwater systems only.

The Problem

When exhibiting large fish (and especially 'dirty' ones) you owe it to the fish to provide clean living conditions particularly when you appreciate that fish are, to use David Ford's apt analogy, 'Swimming in their own loo.' This becomes increasingly important when the Fish Show is over a whole weekend as the fish could easily become stressed due to deteriorating conditions.

Here are two prototype 'filter tanks', entered into the British Open Championship at a recent Festival of Fishkeeping.

You can see that each tank has a
partitioned off 'end chamber' in
which a small filtration unit is housed.

The tank on the left contained a Fire Eel
with a Scobiancistrus aureatus next door.

This photograph shows an end
view of the Fire Eel's tank
on a later occasion and the
submersed power filter is
clearly visible.

The Bracklesham Study

I "road-tested" chemical filtration media on three tanks at Bracklesham, one used for showing fish, the other two as holding tanks.

My three tank set-ups are described below:

1) Show tank (for 8 inch cichlid)

Dimensions: 18 x 15 x 12 inches (450mm x 380mm x 300mm).

Tank design: I used a Show tank with a side-chamber, similar to that shown in the
                   FBAS Judges and Standards News Sheet, number 1-04.

Filtration and heating: A standard air-driven corner filter was placed in the tank's
                                  The filter contained one (3.7 oz/105g) pouch of Nitra-
                                   Zorb plus four tablespoons of Ammo-Chips®.
                                   The side chamber also housed a small internal power filter
                                   and a 50 watt heater-stat. No water changes were made.

2) Two holding tanks (for my Danios, Rasboras and Characins)
Dimensions: 24 x 12 x 12 inches (600mm x 300mm x 300mm, eight 2-3 inch fish)
                  and 18 x 10 x 10 (450mm x 250mm x 250mm, six 2-3 inch fish).
                  These tanks had drilled Perspex partitions.
Filtration and heating: I used a standard air-driven corner filter.
                                  This contained half the contents of a Nitra-Zorb™ pouch
                                  plus 4 tablespoons of Ammo-Chips®.
                                  Each tank also had a small internal power filter connected
                                  to a spray bar, plus a 50 watt heater-stat.
                                  No water changes were made.

Note: It is important that the Nitra-Zorb™ and Ammo-Chips® are rinsed thoroughly before use, otherwise the water will turn cloudy!


I tested the nitrate, nitrite and ammonia levels in all three tanks.
The results are given in milligrams per litre (mg/L) which is the same as "parts per million" (ppm).

The water tests were made at 24 hours (to represent a 1 day Show) and 48 hours (to represent a 2 day/weekend Show). All 3 tanks gave the same readings, as follows:

Water test:        Beginning                         24 hours                 48 hours

Nitrate             below 12.5*                        below 12.5              below 12.5
Nitrite              not tested                          below 0.1                below 0.1
Ammonia            not tested                          zero                       zero

*Water tested for nitrate before filling the tank.


Using identical tank systems, I compared the effects of:
No filtration vs. Nitra-Zorb alone vs. Ammo-Chips® alone.

Results after 48 hours

Water test          unfiltered              Nitra-Zorb only          Ammo-Chips® only
                   (no chemical media)

Nitrate              12.5 mg/L                    12.5 mg/L                    12.5 mg/L
Nitrite                0.5 mg/L                below 0.1 mg/L                  0.25 mg/L
Ammonia            0.5 - 1.0 mg/L             0.5 -1.0 mg/L                 zero


In my view, an advantage of using chemical filtration is that it can easily be installed in the Show tanks, and also in temporary holding tanks at the accommodation (such as in my chalet at Bracklesham) - a definite advantage over biological filtration.

The media are also rechargeable, which saves on cost. By using these chemical filtration media, it wasn't necessary to make water changes during the weekend Show - this was a first in my experience!

In addition to Bracklesham, I have also used this method of filtration at two other weekend Shows: the Isle of Wight Open Show and BAF (British Aquarist Festival, Manchester). Over these 2-day Shows there was no deterioration or damage to the fish's fins. These filtration media had no effect on pH.

As shown in my comparative study, the best results are achieved when using a combination of Nitra-Zorb plus Ammo-Chips®.

Want to know more?

For more information about chemical filtration, write to Peter Burgess at:

The Aquarian Advisory Service,
PO Box 5059, Melton Mowbray,
Leicestershire LE14 4ZN.

Or email your enquiry directly to Peter:

Both Peter and John will be at the Festival of Fishkeeping and Water Gardening Weekend, Hayling Island, October 14-16, 2005. Hope to see you there!

For further information about fish and fish keeping, visit us at

Last updated September 2005