Here we answer frequently asked questions about filters:

Why do the NaturaGart filtration media get so dirty?

What do I do if I do not want the the water so extremely clear?

How much mud goes into a NaturaGart filter?

What determines the maintenance intervals of a filter?

How can I prolong maintenance intervals?

For how long can I leave the dirt inside the filter?

What do I have to do if I want to stabilise a plant-less fish pond with a NaturaGart filter?

Why does black slime sometimes form on the filtering media?

I use one of your filters and have crystal clear water. Nevertheless, ammonium and nitrite values are too high. Why doesn't the filter work properly?

Why is emphasis in NaturaGart filters on mechanical cleaning?

Why do the filtering foams sometimes float?

What is important for the operating security of filters?

Answers:

Why do the NaturaGart filtration media get so dirty?
The filter itself doesn't produce mud, of course. It extracts it from your pond, and NaturaGart filters are especially effective doing this. The smallest pore size is half that of what most other suppliers offer. The fine filters reach 60ppi (pores per inch), whereas many competitors' only have 30ppi. This is the reason why so much dirt stays in the filter.

The NaturaGart filter's job is to extract all suspended matter from the water. With the correct circulation rate it does this perfectly. Then the dirt can be found where it was deposited: in the filter. The better the filter works, the faster it has gathered all the mud. Initially this will lead to very dirty filters. Later, the cleaning intervals increase to a few weeks. 

What do I do if I do not want the water so extremely clear?
Reduce the pump's running time. Use a timer to alternate 15 minute running time and pauses. That will halve your electricity consumption.

How much mud goes into a NaturaGart filter?
Each foam element can absorb about 1kg of mud, that makes 8kg for the vertical filter.

The organic mats take up to 300 grams per unit, so that means about 9kg for a standard filter. These are excellent values for stockpiling capacity.

What determines the maintenance intervals for a filter?
If your pond produces 9 kilos of sludge per week (for example because you feed your fish so much) then the filter will be full after one week. Feed half the amount and it will take a week longer to fill up.

To the feed add pollen, leaves and so on. Nutrients are more or less deliberately introduced in every pond. The filter then extracts them. The more that is introduced, the more has to be extracted via the filter to maintain the pond in equilibrium.

How can I prolong maintenance intervals?
In the pond: Reduce the introduction of nutrients. This is the most effective way to solve the problem. Many things you can do nothing against (eg. pollen).

In the filter: Increase the filtration surface, for example with another standard filter. If you have to extract 9kg per week and one filter 'only' manages 9kg, then two filters last two weeks.

For how long can I leave the dirt inside the filter?
Most ponds have relatively short maintenance intervals in the beginning because these is still relatively much mud in the pond. Well kept ponds have theoretical intervals of several months. In practice you should clean filters every 4-6 weeks because the organic residue has to be removed from the system, because inside the filter it still is part of the pond. They are decomposed like compost and thus go back into the pond.

What do I have to do if I want to stabilise a plant-less fish pond with a NaturaGart filter?
Fish are part of a biological system. They give plants carbon dioxide and other nutrients and in exchange obtain oxygen and elimination of toxics.

By doing away with plants this biological system is substituted by a technological compromise solution. All that is normally regulated with help of plants, you will have to substitute with extra monitoring, analysing and knowledge. At some point you will reach your limits - the system becomes unstable and the fish become ill or die.

The most important measure in bare fish basins is to enlarge the colonising surface for bacteria that transform ammonium and nitrite into the less harmful nitrate.

You can also use the NaturaGart filtration systems for this: You can load the VF-8 modules with very coarse oxi-foam. Water then slowly trickles through this huge surface and is oxidised. In our experience natural systems are colonised in few days. In very technical situations you can use starter bacteria.

Take into account that nitrite can peak after 5-10 days. This happens if the decomposition of ammonium to nitrite is quicker than faster than the further decomposition into nitrate. Some systems are fully functional after 3 days, other take 3 weeks. There is no way to reliable control this at bacterial level. You should reduce feeding in the start-up phase to avoid the peak from becoming too high. Under these circumstances, according to our experience, there are no problems.

Why does black slime sometimes form on the filtering media? You have probably used a UV system that has massively affected algae. The rests of algae form this typical slime. Wash out the foam modules or change the organic mats. The problem disappears once the algae are under control.

I use one of your filters and have crystal clear water. Nevertheless, ammonium and nitrite values are too high. Why doesn't the filter work properly?
That is not a filter problem but rather a construction problem the pond has. Filter can only extract particles from the water. In this way, for example, fish excrements are removed from the water. With this technology, however, you cannot extract urine from the water. The tiny nitrogen molecules effortlessly pass through the finest filters. Put simply: Mechanical filters are always only good against excrement, not against urine.

In natural ponds the problem does not occur because the plants decompose the urine components. If you do away with plants you have no system to limit these toxics.

Why does emphasis in NaturaGart filters lie on mechanical cleaning?
Prevention! Where nothing rots, much of the toxic residue doesn't even begin to form and doesn't have to be treated with a biological filter.

If you build a natural pond, you will not get any problems, because every grain of sand and every plant leaf has this function. This needn't be purchased additionally.

It is also simple to group several VF-8 modules into large biological filtering stations. We supply the oxy foam in the corresponding sizes.

Why do the filtering foams sometimes float up?
Nearly all plastics are lighter than water, as are the filtering foams. Since they are about 5mm larger than the frame of the box, they are clamped into place and cannot float away. Additionally they are held in place with a rod of wire.
Normally about 1kg of sludge accumulates in every block of foam. This causes the foam to become so heavy that it cannot float upward.
In rare cases it can happen that the surface of even the coarse foams clogs up without it being completely full of sludge yet. This situation sometimes happens at the beginning of April, when thread algae enter a special reproduction cycle. 5-10mm long threads drift through the pond, often with a small air bubble that gives then buoyancy. When these appear in large numbers, they can occasionally clog up the filters without the foam having become heavy yet. The rising water level then causes the elements to float up. This really only affects the topmost coarse foams. Since the others remain in position they get dirty more quickly, but still supply the same quality of water.
In some ponds there are high concentrations of large particles. Please use a coarse filter in such cases. This solves the problem immediately.
If this is not the case, consult the instructions. You may have forgotten to re-insert the wire rods or perhaps pressed out the foam too much so that they have become smaller.
The stretch them back into their normal size. We supply them 5mm larger than the inside measure of the filter body.
Under these circumstances they won't float up!

What is important for the operating security of filters?
Nearly all filters have  a weak spot that form our point of view is not given sufficient attention: Normally the water leaves the sealed pond and is pumped through pipes into the filter and back again from there. If a problem exists there, the pond will be pumped empty.
Examples of problems that we have experienced:
- Pipes are installed underground and are damaged with a spade while gardening.
- Playing children dismantle the filter or the pipes.
- Large animals topple the filter over.
- Pipe connections come loose.
- Vandalism.
- A falling branch rips off a pipe.
- Terrace paving is undermined by animals.

Using the NaturaGart Filtration Trench or Target Suction Technology, loss of water is limited to the top 40cm. In other cases the pond is pumped empty.
This is easy to avoid with a floating switch that turns off the pump if water drops below a certain level.