<div align=center><span style='font-size:14pt;line-height:100%'> <span style='color:purple'>UV Filtration/Steriliser
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I have used a UV filter for some time now and never had a problem with it. Before I go on I should mention what a UV filter does. Although more often referred to as a filter it's not. It is in fact a steriliser and is claimed to kill bacteria, algae and even viruses. I have always accepted that as fact and I still do. Only a month or two ago I was attracted to a thread on another sites message board. (A MSN group) It made reference to a fact or, may be a fictional idea, that it's use lowers a fishes immune system. This hypothesis was based on the idea that when a UV filter is used it makes the water sterile. This to a degree is true but, can only be applied to the water as it leaves the UV unit. Once the water is back in the tank it will become rapidly recontaminated. Not to the same levels as to what is was before but non the less it will become recontaminated. What has to be taken into account is the fact that not all bacteria are what might be deemed as free swimming. Remember all our friendly ones that colonise our filters, rocks, substrate and even the glass, well remember this as well, you also get the non friendly type. Both can and, do under what we call the ideal for our fish, procreate at a rapid rate of knots. Back to the point and the implications of it all. It was implied that fish reared/kept in systems using UVF/S's although perfectly healthy and in prime condition are more susceptible to disease when moved to a non UVF/S setup. I as I stated in the beginning, I have never had any problems and I am constantly having to move fish out of my sump run tanks which is where my UVF/S is incorporated. I would also like to mention that I have never had any reports on fish I have sold that would contradict my last statement. I look forward to your opinions,