I have a Bermuda 4000 UV bio filter in my 1125L pond with 4500 Lph pumping through it. The UV bulb is blown and I have a replacement on order but in the process have met with lots of conflicting advice about how effective this setup should be.
My understanding is that the flow rate determines whether the water is sterilised or just clarified (ie the extent of the cellular damage caused by the UV light) - but I can't get a definitive answer on what is best for my pond. My local aquatics shop was hell bent on selling me an extra steriliser (£100) rather than a replacement 7W bulb (£10).
The pump and filter are over-spec'd for the pond (1125L pond filtering 4000Lph should be turning the water about 4 times per hour) - but this may be too fast for the UV to actually be doing any good.
I only keep goldfish, not koi and have plenty of surface cover planting - or will do when the lilies grow back).
Can anyone give me some genuine advice please as my local pet shop has, on a few occasions now, tried to get me to spend excessively when it was not really necessary.
Thanks.
