U.V. Sterilizer
- Thread starter JeLeAk
- Start date
I had this discussion with Wayne on another topic. I asked if what kind of energy is required to kill germs such as viruses and bacteria. And but I never received an answer from him.
So here goes a little lesson on ultraviolet light. There are 3 types of UV light, UV-A, UV-B and UV-C. Almost all the UV sterilizer produce a UV-C which is has wavelength of 200 to 280 angstrom. From physics we know that smaller the wavelength, greater the frequency and thus greater energy produce compared to UV in the A group, which has larger wavelength. 254 angstrom is the so called, germicidal UV that can kill just about any known viruses and bacteria and various other pathogens. The UV sterilizer designed for aquarium produce a about 150A, which is more than sufficient to kill any pathogens found in the water. The wattage rating does not any equate to the what I call the killing power. There are units with very wattage that can produce wavelengths lower than 250A.
On the other hand x-rays produce wavelength about 5.4A which can kill human tissue after longer exposure period since the energy produce by these are much greater than UV waves.
In other words, good quality UV sterilizer can kill many of the pathogens in the your water. The draw back to this is that it can also kill many of the useful pathogens such as bacteria and algae. I recommend using your UV sterilizer as needed and not run it continuously like a filter.
Rohn
PS I am in hurry to get to work. Will explain/debate any scientific aspect of this topic if anyone request.
So here goes a little lesson on ultraviolet light. There are 3 types of UV light, UV-A, UV-B and UV-C. Almost all the UV sterilizer produce a UV-C which is has wavelength of 200 to 280 angstrom. From physics we know that smaller the wavelength, greater the frequency and thus greater energy produce compared to UV in the A group, which has larger wavelength. 254 angstrom is the so called, germicidal UV that can kill just about any known viruses and bacteria and various other pathogens. The UV sterilizer designed for aquarium produce a about 150A, which is more than sufficient to kill any pathogens found in the water. The wattage rating does not any equate to the what I call the killing power. There are units with very wattage that can produce wavelengths lower than 250A.
On the other hand x-rays produce wavelength about 5.4A which can kill human tissue after longer exposure period since the energy produce by these are much greater than UV waves.
In other words, good quality UV sterilizer can kill many of the pathogens in the your water. The draw back to this is that it can also kill many of the useful pathogens such as bacteria and algae. I recommend using your UV sterilizer as needed and not run it continuously like a filter.
Rohn
PS I am in hurry to get to work. Will explain/debate any scientific aspect of this topic if anyone request.
Sorry for not replying in the original post/mail. I fully agree with the split between UV-A,-B,-C, and that -A and -B are far more effective. Unfortunately I believe most units kick out -c. More relevant is that you still require a certain intensity, and the intensitys required to kill ich, and the other parasitic nasties these are bought to combat are far, far higher than those required to kill bacteria and algaes. the intensities I saw most recently were in Delbeek and Sprung Vol 3, and are referenced from a reputable source.
Given the short life span of the bulbs, high maintenance required and intensities far higher than are required for pond 'greenwater units' (where UV is effective) I strongly doubt these are much help for what most people buy them for, especially when you consider the old chestnut that they only kill what's in them, not what isn't.
Given the short life span of the bulbs, high maintenance required and intensities far higher than are required for pond 'greenwater units' (where UV is effective) I strongly doubt these are much help for what most people buy them for, especially when you consider the old chestnut that they only kill what's in them, not what isn't.
Sorry, I still don't have the correct numbers, but I did look yester day and the intensities required to kill protozoan cysts/tomonts compared to bacteria, algae, were approximately 2 orders of magnitude higher. I doubt these things are overbuilt for killing algae to that extent. When you take that into account, the fact that the bulb will drop in output by about 40% in 6 months and the fact you have to keep everything clean I find it less and less believable that these things do what they are meant to. Maybe the high output systems that are sold for commercial setups that output UV-B and UV-C are useful (likely are), but the low pressure, hobbyist units, no I don't think so. Somebody prove me wrong - on the box, what does it say the output is?