What is a UVC and will it improve my pond water?

UVCs or Ultraviolet Clarifiers are capable of making green pond water clear, but they do not make it clean. Without the help of a biological filter or a very healthy pond, UVCs used on their own are just making the ingredients for a pond polluting time bomb.

The term Ultraviolet Clarifier applies to a piece of pond equipment used to the green free floating microscopic that make fish pond water green. The unit is usually fitted on the hose line between the pump in the pond and before it enters a biological filtration unit. The water is pumped from the pond through the unit which contains an Ultraviolet lamp. The water is circulated around the lamp bulb and then proceeds on to the filtration unit. The effect this has on the water is that any algae present are severely damaged. It also causes the individual cells of algae to clump together and thus they are more easily filtered out of the water in the biological filtration medium and then digested by the bacteria that inhabit it.

Let me tell you a story....

One upon a time when products for treating pond water with ultra violet light were first marketed, they were called Ultraviolet Sterilizers because true the development of most things in the world of water garden hardware, the idea had been filtched from the technology employed in sterilizing hospital water supplies. In hospitals for some years, tubes contains ultra-violet lights had been used in killing bacteria in the water. When used in a pond situation, the intensely sterilzing dose of ultraviolet not only killed the algae outright but killed a lot of the beneficial bacteria in the pond. The 'knock-on' effect of this was that the fish became listless and much more prone to disease. The bacteria that fish live with all their lives have the capacity to turn against them and inflict them with manner of obnoxious ailments, but if the the conditions of the pond are balanced then these otherwise infectious bacteria serve to boost their immune system in a similar sort of way that our methods of vaccinaton of a small dose of a diease help us fight that disease. With the disease present in our sytems our bodies can develop antibodies that will fight the disease and prevent us getting a real dose of it.

Another possibility is that an over effective dose of ultraviolet light might affect the development of a new filter, rather than helping it. When you are hoping to build up a population of bacteria in your filter, the ultra violet lamp is blasting every micro bug with an ambition to populate the bio-filter that passes through it. 

So, UVCs are not as powerful as they were for the size of pond for which they are recommended. This meant that although they seemed just as effective, they were cheaper to run and the bulbs needed changing less often. But owners of new ponds beware of the possibilities that even a small dose of UV can have a detrimental effect on benign bacteria, and so initially refrain from the use of an ultraviolet clarifier if you want you pond and filter to become established as quickly as possible. So I would refrain from using them on a newly built pond for at least 4 weeks in summer and 8 weeks in spring and autumn, until the biological system has built up in the pond.

 NEW POND SYNDROME

In the course of the development and in maintaining the sustainablity of the eco-system of a pond, a
UVC may be detrimental. It is only there to satisfy the needs of
the pondkeeper who wants to see into his pond. It adds nothing to  help
with the break up of all the pollutants in a pond. In fact it may only hinders the development of the bacteria that break up the detritus and the pollutants in the pond. On new ponds you can tell what is happening by doing regular water checks. In a healthy pond the faeces of the fish and uneaten fish food  are initially broke down by a group of heterotrophic bacteria in a process called mineralisation. These produce highly toxic ammonia compounds that would quickly make the pond sagnant if it were not for some oxygen dependent bacteria (aerobic bacteria) called nitrosomonas that, with the use of oxygen,  can break up the ammonia compounds to nitrites. Nitrites are quite toxic too, but another group of bacteria (nitrobacter) can also use oxygen again to make these into nitrates. These are relatively less harmful to the fish and tend to make the water green because they feed plant life and that includes the single celled plant life, algae. This is when you what you got your UVC to zap.

In a new pond, if there is too many fish in the pond, the ammonia consuming bacteria, nitrosomonas, can build up quite quickly and so the ammonia trauma can soon subside, but the nitrobacter that are meant to tackle the The Oase Bitron 36c is a hefty £240 but it could cope with a 60,000 litre pond.nitrites are either much slower at getting established or they take much longer to process them, so the level of nitrites build up to quite extreme levels where they even poison the bacteria themselves. The effect on the fish is that the nitrites get into their blood systems replacing the oxygen and so they start to gasp at the surface for air. A salt treatment can reduce the effects of the nitrite, but it will only delay the day of judgement. Small water changes offer the best chance of reducing the effects of the nitrites whilst the bacteria levels build up.
It is the peaks of the ammonia, nitrates and nitrates that define this as the effects of NPS (New Pond Syndrome or New Filter Syndrome as some Koi keepers call it). As the ammonia level in the water rises and falls, you will find that as the ammonia peaks the nitrite level begins to rise. This will reach a similar peak and then begin to fall as the nitrate level rises. This is when you may find your pond turning green. Dont turn on the UVC until the nitrite level seems to be under control i.e reading zero. 

So you can imagine from this that it might be quite possible to overdo the blasting with UVs at any stage in the development and life of a pond and in fact there are a large number of fish keepers that would refrain from using their UVC for more than 2 hours a day for this very reason. Also you can see how important it is to get the correct size of UVC for your pond, particularly if it is more than just a pool for fish. A way of avoiding this is to get a biological filter that corresponds to the volume of water in your pond and the quantity or weight of fish and get the UV that the manufacturer of the bio-filter suggests.

So what happens if you were to use a UVC without a proper biological filter installed in the system?

Using the UVC without the benefit of the various bacteria from breaking up and thus removing the toxic chemicals from the pond environment, and if anything the UVC actually being a detriment to the proper establishemnt of those bacteria, the pollutants are just going to steadiy build up. You wont see any effect on the colour of the water. It may for the large part remain clear. It will certainly remain clear at the point when nothing can live in it and the ammonia and nitrites have risen to such a level that even algae can survive in it.

Tips on Choosing a Good UVC

As you can see from the discussion above that getting the right UVC for the pond is to a certain extent critical. The size comes as recommended by the manufacturer for your size of pond. A conscientious manufacturer may also consider the number of fish or the weight of fish in your pond, although I would have thought that this would more directly relate to the size of the biological filter required.

The Bitron use of magnets to help prevent calcification.Even though modern UVCs only need servicing once every year, I would also consider the ease of maintenance. Fiddling with tiny screws that disappear into the mire the first time you extract them, or when it comes to removing the lamp bulb, the connecting pins have oxidized themselves into the sockets, you end up wanting to launch the thing into space at the next irritation. That generally comes with the cracking of the delicate 'quartz' sleeve that the tube sits in. And so its another round trip to the aquatic centre and a jaw dropping bill for the new sleeve that seems to cost the best part of the cost of the UVC in the first place.

The Oase in creating the range of UVCs that they call Bitrons seem to have eliminated many of the hassles in UVC maintenance. The sleeve that contains the UV lamp is self-cleaning anyway.  The innovative Oase automated cleaning system is activated by water flowing around the quartz tube and prevents sludge and slime from settling and thereby ensures maximum UV radiation. The Bitron 18C model, and above, include permanent magnets to prevent calcium deposits (scale) from forming, thereby improving functionality.

The easily adjustable bypass system controls the flow over the UV light and achieves optimum clarification - but it also allows you to trim the performance of the UV to the flow of water from the pump and through the filter. All Oase Bitron Ultraviolet Clarifiers are designed to fit directly onto Oase Biotec and Proficlear filters. Oase recommend that UV lights be replaced after 10000 operating hours to ensure full strength radiation of the UV rays.

The lamp can be accessed without tools and at the push of a button and a twist of the back of the lamp housing. You need to know what you are doing because everything is a tight firm fit, so it it is fairly tamper-proof from the attentions of small children.