Ammonia (part 2)

In In Part 1, we saw that ammonia concentrations above 0.1 milligrams per liter of water are harmful to fish. Ammonia is a waste product created by the digestion of proteins by our pond inhabitants. In a well-functioning pond with a good biological filter, we hardly measure any ammonia (ammonia ( _NH3 ) and ammonium ( _NH4 ⁺ ) combined). However, if we measure an increase in this level, all the alarm bells should ring, and we will have to take measures to protect our fish from disease or even death.

How does an ammonia peak occur?

There are several possible causes for this:

We have a new pond, the biological filter of which does not yet contain enough nitrifying bacteria to break down the released ammonia.
Our biological filter is too small (insufficient attachment surface for nitrifying bacteria) to break down the entire supply of ammonia.
We fed too enthusiastically in the spring, while the filter had not yet fully developed.
You've significantly expanded your fish stock. Your bacterial colony needs time to grow along with the increased food supply.
We used medication (poison) that killed the bacteria in the filter.
We have replaced the filter material in the filter, which means everything has to be restarted.
The water and/or air pump has failed, depriving the bacteria of food or causing a lack of oxygen. Consequently, the bacteria have died.
Insufficient water was replaced, causing the KH to be depleted. This caused a pH crash, killing the bacteria.
The filter has dried out, causing the bacteria to die.

In short, quite a lot can go wrong, this list is not exhaustive, but shows the most common causes.

What to do in case of an ammonia peak?

The most important thing is to address the cause. If you don't solve the problem, any further steps are pointless. In the event of an ammonia spike, consider the following actions:

Refresh to reduce the amount of ammonia to a harmless level.
Solving the problem (!!)
Zeolite or a ammonia-binding use an agent to reduce the ammonia concentration.

Function and use of zeolite

Zeolite is a porous volcanic rock with a very fine structure. It is capable of "trapping" ammonium molecules within this structure. By adding zeolite to your system where there is a lot of water movement (for example, at the filter outlet), you can reduce ammonia levels. When the ammonia level in the pond drops to zero after adding zeolite, you can gradually remove the zeolite from the system at intervals of a few days, giving the biological filter time to take over without the concentration rising to dangerous levels. By taking frequent measurements, you can accurately control this process. If you measure an increase after removing some of the zeolite, wait a little longer before removing the next portion (until the value returns to zero). With a significant increase (> 0.2 mg/l ammonia), zeolite should be added again and the water should be changed again.

Zeolite can become saturated, meaning it no longer absorbs ammonium. You'll notice this when the level starts to rise again without removing any of the zeolite. The zeolite then needs to be regenerated. To do this, place the zeolite in an aerated salt bath (50 grams of salt per liter). This releases the ammonium back into the water. Dispose of this water down the drain. After the zeolite has been thoroughly rinsed, it is ready for the next use. If the ammonia peak persists for a long time, the zeolite will also need to be regenerated or replaced periodically. In that case, it's helpful to have two bags of zeolite on hand, one for use in the pond and the other for regenerating.