PROTEIN SKIMMERS. The new piece of kit for pondkeepers that could be a life saver

If you have noticed foam forming around the bottom of the waterfall or in the biological filter, it may be a sign that the new pond and filtration system is not fully functional yet, but if has been lingering around for some time it may be indicative of larger problem serious enough to cause the death of your fish. A protein skimmer may be an expensive but it will be a sure-fire piece kit that helps you avoid  anything like this being a problem.

DOCs (Dissolved Organic Matter) the bane of the serious fishkeeper

As winter approaches and water temperatures cool, the seasonal change will exacerbate the problem that foam on the pond may be indicative of. One contributing factor may be excessive runoff from surrounding flowerbeds of soil sediment or accumulated debris around the pond, also trees shedding their leaves into the pond. Certain species like yew, oak, willow and elder can be particularly toxic, but also some innocuous small leaved types of Acer, although not toxic in themselves, break down very rapidly and can add quite a bit of organic matter to the water, which to a certain extent dissolves in it quite quickly. This organic matter is referred to with dread by Koi keepers as DOCs, 'dissolved organic compounds'. These are already present in the dampness of the soil and so can create an instant foam as soon as it splashes in.

Protein skimmers use the strange behaviour of DOCs, when reacting to the presence of water, to isolate them from the water.

It is the protein or molecules of organic matter in the soil that have this foaming effect. When these organic molecules are exposed to air they all seem to line themselves up on the surface of the water, this is because they are 'surfactants'. This means that when they are in water, they have a 'non-polar' end, which scientists call hydrophobic or "water hating," and so they align themselves with that end of the molecule sticking out of the water in the air. Normally that would be the surface of the pond or the water in the filter. The odd thing is that if you spray in bubbles of air or oxygen into the water, the molecules will stick to the surface of the bubbles in the same way they stick to the surface of any water. This also has the effect of preserving the bubble, making it more enduring. Protein skimmers make use of this fact by manufacturing and collecting these bubbles for removal. By adding small bubbles to the water in a container, more air surface is created, which in turn means more surfactants (DOCs) are attracted and because the bubbles rise to the surface of the water, they can easily be removed.  This has an added benefit for the Koi keepers because along with all these organic chemicals are a lot of other pollutant that may not ordinarily be picked up by a biological filter, like heavy metals and tap water pollutants.

So how come these dissolved organic compounds are a threat to fishkeepers?

The answer may lie in the fact that there is a limit to how much of anything you can dissolve in water, and if something is already in solution with it, it prevents another thing from getting in there. So if the water is chock-a-bloc with DOCs then that doesn't leave much room for oxygen. Although you may be pumping in loads and loads of air or even pure oxygen into the water all it is managing to do is make bubbles, which the DOCS play 'Ring-a-Ring of Roses' round. Add to this the effect on aerobic bacteria that should be there in the biological filter that are meant to be processing the normal run-of-the-mill fishwaste, they are further stimulated by the presence of the DOCs. It causes them to proliferate, but so does their demand for oxygen, because that is what they use to break up the organic matter. The oxygen level is further depleted as a result, albeit temporarily but possibly with fatal results, especially if the filter has not properly matured or if it is timed perfectly with a big freeze.

Protein skimmers are a pretty new innovation for ponds and they are mostly used within the realms of the Koi enthusiasts who have pretty clean ponds anyway. At over £200 for something with the sort of capacity to cope with a fairly large fish pond of around 1000 gallons, it may be better to consider where the foam and thus the DOCs may be coming from and controlling them at source.

If the foam is a result of DOCs, we can examine the possibilities of how they may have arrived in the pond. Fish food is one possible source, firstly if it is not eaten and secondly if it is high protein food given to the fish at a time when their digestions cannot cope, it just gets deposited back in the pond.  Some colourants, medications and vitamin additives are other sources. There may also be a source from something that has been there since day one, plants in aquatic baskets. Often bored Koi can bump and titivate these baskets dispersing the contents all around the pond. They think its great fun but it can play havoc with your filtration system.....

So in general what conclusions can you draw from this? What tips should we take on board in order to avoid any problems that may cause potentially devastating foaming in the future?

1. Get some effective mechanical filtration that can efficiently, easily and regularly with little effort be back flushed to waste.

2. Turn the whole pond volume of water over every two hours through the mechanical filtration.

3. If the above two are difficult - then at least do something about run off from soil, grass and paving and also detritus and leaves blowing in. In fact net the pond in Autumn just to make sure.

4. Also check the planting baskets if there are any. I would suggest replanting them with fabric liners and heavy pebbles on the surface.

5. Prime the filter with bacteria, either proprietary compound or with a starter from chum's filter. Then run it with just a few second-rate fish to see what the reaction is. Adding lots of fish in one fell swoop spells DISASTER.

6. If you dont believe me, arm yourself with a water test kit and test daily for the first month and then at least weekly from then on. You should test regularly anyway, and any sign of ammonia  - panic.

7. Do small water changes regularly rather than huge amounts that may strain the system and do more harm than good.

8. Feed the fish only what they need and the right formulation for the time of year. Net off anything they do not eat. Dont pre-soak the food. This instantly releases undesirable compounds straight into the water.

9. To help with the detritus, get yourself a good pond skimmer. It will keep a lot of the detritus from becoming a problem before it even has time to soak any water up then sink to the bottom and start to become a problem.

10. If you really feel as though you could afford a protein skimmer, you can rest assured that they do get to the root of the problems that so many ponds have, i.e. the basic material that causes pollution in the pond and even some of the elements and compounds that bio-filters cant deal with. Mind you, most ponds (not generally Koi ponds) are so full of muck that even the biggest Protein skimmer would be lost in the mire.

11. Keep up a routine of maintenance especially when there are seasonal changes due, winter through to spring, summer autumn winter, they all have their problems. This is what arms you for what may come weather-wise, and will cover you and your fish more than any amount of expensive equipment.

Here is the PR blurb for a Tornado Protein Skimmer as from Absolute Koi where you can buy it for £245:

“The Tornado protein skimmer is a combination of three different filter systems. The filter operates biological, mechanical and chemical. The principle of the skimming of salt water is not new and has been successfully used for years in aquarium filtration. Thanks to the unique, patented, design of the Tornado protein skimmer, it is now possible to apply the principle of protein skimming in fresh water.

"The Tornado Protein Skimmer has a Pump capacity between 1500 litre and 5000 litre per hour.

How the Tornado Protein Skimmer works:

"The surface of an air bubble attracts dissolved substances out of the water. Because of the adhesion of the bubbles these substances, like chemicals, waste particles, colourants and algae, are concentrated. By means of a venturi,9The Tornado Protein Skimmer air is mixed with water. By forcing this mixture through the filter material (the white “KNS” bio rings) to a lower drain, there is a long contact between air and water. This changes the surface tension of the water continuously and a thick foam arises. The foam is separated from the cleared water by a grid and drained. Different kinds of pollution are caught in the foam and drained. This makes the filter Tornado Protein Skimmer self-cleaning. Dissolved substances like; phosphates, ammonia, humic acids, colourants, proteins and a number of heavy metals, are filtered out of the water and drained together with the foam. The extraction of dissolved substances is not possible with normal filters and can only be done if chemicals are added.

"The Tornado Protein Skimmer has various advantages:
The Tornado Protein Skimmer Stabilizes pH
The Tornado Protein skimmer Removes colorants
The Tornado Protein skimmer Increases dissolved oxygen
The Tornado Protein skimmer doesn't depend on bacteria and works as soon as the pump is running
The Tornado Protein skimmer Prevents fish disease as a result of bad water quality"