I've been seeing some threads pop up regarding U.V. sterilizers/clarifiers and I'm hoping ]v[FK can benefit from a thread concentrating on an introduction to them to help members with some basic information. I'd like to try to do my best to describe loosely how they work and what benefits maybe yielded from their use. As well as clear up some myths associated with them. First I'll tackle how they work.
How they Work-
U.V. sterilizers/clarifiers work by exposing water to short wave UVC light which ionizes many atoms and molecules. This kills suspended bacteria and many viruses in the water column. It also has the added benefit of improving Redox in an aquarium. Proper Redox balance aids in fish immunity to disease,infection and their ability to heal. Therefore proper U.V. sterilization aids your tanks overall health two fold. 1-by killing many bacteria and viruses and 2-by improving fish immunity through balanced Redox.
How Effective are They-
How effective they are is based on water flow, dwell/exposure time and uv sterilization level.
Water Flow, Dwell/exposure Time UV Sterilization Level-
Necessary dwell/exposure time is affected by many factors including suspended particles in the water column, whether the water is in direct contact with the UV or if it's through a quartz sleeve as well as the distance of the water from the exposure source in the unit. Unfortunately most manufactures give little to no information in regards to this about their product. Usually you'll only know whether the UV is in direct contact or through a sleeve and perhaps the wavelength of the radiation being emitted by the UV light. So we'll use some very basic calculations to determine dwell/exposure time in relation to flow. Mind you these calculations are based on 1-low water turbidity 2-A water temperature between 20 C (68 F) and 40 C (104 F) 3-a gap of .3 mm or less between the bulb or quartz sleeve and the wall of the unit 4-good water flow pattern inside the aquarium or pond. 5-a clean Quartz sleeve/lamp and a hot cathode low pressure UV bulb/lamp with less than 6 months continuous use. As such these are not definitive calculations but a guideline. If you wish to increase efficiency you should decrease the gph/increase dwell time as much as possible to make the UV sterilizer/clarifier more effective.
Words of Warning-
The vast majority of U.V. sterilizers on the market aren't created equal. In general you get what you pay for and there is no exception here. The affordable intank sterilizers/clarifiers are in general inferior to their inline counterparts. They can generally be counted on though to help control algae and in some instances the higher wattage units will perform some degree of Level One Sterilization. All models though should generally increase the Redox of your aquarium. Another note worthy bit of advice is when using the intank self powered units they're best placed near the output of your existing filtration system to increase it's effectiveness.
Dispelling Some Myths-
Biological Filtration Killer-
U.V. sterilizers/clarifiers willnot kill beneficial biological bacteria in your tank. The basis for the biological filtration in your tank is within your filter and to a lesser extent your substrate,glass,ornaments and water column. The least amount of concentration being in the water column which is the only bacteria that can be destroyed by the U.V. as they are the only bacteria being passed through it's radiation. As such no matter how effective the UV sterilizer/clarifier is it should never effect your biological filtration detrimentally.
No more Algae-
No matter how effective the sterilizer/clarifier is it's incapable of filtering all your water at once. As such the sterilized water returned to the water column is constantly mixing with un-sterilized water and makes total sterilization impossible. So while it will slow proliferation of algae and generally keep your water clear it won't stop algae from growing in your tank all together.
No more Disease-
It's important to note a UV sterilizer no matter how effective does not rid a tank of disease. It merely kills most bacteria and viruses suspended in the water column. That means some will also survive in the water column and doesn't even consider what might be living within ornaments, substrate, glass or fish. Just as with algae it merely helps control the rate of proliferation and to an extent concentration of hazardous organisms in your tank's water column it does not eliminate them all.
**While I know this isn't a comprehensive description of U.V. sterilizers/clarifiers I do hope it's accurate and helps to give a basic understanding of them.
**As you may have noticed Redox is highlighted in green I did this to indicate I embedded a link in the word. If you click on the word you will be directed to link that more fully explains Redox. Here's a **couple of more links that you may find helpful and are just some of the sources of information I found regarding U.V. sterilizers/clarifiers. **
** Redox ** last updated 12/20/2012
** Ultraviolet Sterilization ** last updated 3/5/2012
** Fish Immune System and UV Sterilization ** last updated 9/6/2012
** UV Sterilizer Problems & Reviews; Ballasts, Submersible Pond, Killing Machine UVC Clarifiers ** last updated 2/4/2012
How they Work-
U.V. sterilizers/clarifiers work by exposing water to short wave UVC light which ionizes many atoms and molecules. This kills suspended bacteria and many viruses in the water column. It also has the added benefit of improving Redox in an aquarium. Proper Redox balance aids in fish immunity to disease,infection and their ability to heal. Therefore proper U.V. sterilization aids your tanks overall health two fold. 1-by killing many bacteria and viruses and 2-by improving fish immunity through balanced Redox.
How Effective are They-
How effective they are is based on water flow, dwell/exposure time and uv sterilization level.
Water Flow, Dwell/exposure Time UV Sterilization Level-
Necessary dwell/exposure time is affected by many factors including suspended particles in the water column, whether the water is in direct contact with the UV or if it's through a quartz sleeve as well as the distance of the water from the exposure source in the unit. Unfortunately most manufactures give little to no information in regards to this about their product. Usually you'll only know whether the UV is in direct contact or through a sleeve and perhaps the wavelength of the radiation being emitted by the UV light. So we'll use some very basic calculations to determine dwell/exposure time in relation to flow. Mind you these calculations are based on 1-low water turbidity 2-A water temperature between 20 C (68 F) and 40 C (104 F) 3-a gap of .3 mm or less between the bulb or quartz sleeve and the wall of the unit 4-good water flow pattern inside the aquarium or pond. 5-a clean Quartz sleeve/lamp and a hot cathode low pressure UV bulb/lamp with less than 6 months continuous use. As such these are not definitive calculations but a guideline. If you wish to increase efficiency you should decrease the gph/increase dwell time as much as possible to make the UV sterilizer/clarifier more effective.
| UV-C Use | Flow Rate (generalized) | Turnover Rate |
| Clarification; (Green water control; Aquarium/Pond) The most popular application for ponds | 40-50 gph per watt (50-60 gph High Exposure/Dwell UV or even 70+ gph with Super High Exposure Pro Clear UV30) | Once per 2-3 hours |
| Level One Sterilization (Bacteria, some Virus) The most common & recommended aquarium application | 20-30 gph per watt (30-35 gph High Exposure/Dwell UV) | 1.5 times per hour |
| Level Two Sterilization (Parasites, “Stubborn” Viruses; Recommended for Swimming Pools) | Under 8 gph per watt (8-12 gph High Exposure/Dwell UV) | 3 to 4 times per hour |
Words of Warning-
The vast majority of U.V. sterilizers on the market aren't created equal. In general you get what you pay for and there is no exception here. The affordable intank sterilizers/clarifiers are in general inferior to their inline counterparts. They can generally be counted on though to help control algae and in some instances the higher wattage units will perform some degree of Level One Sterilization. All models though should generally increase the Redox of your aquarium. Another note worthy bit of advice is when using the intank self powered units they're best placed near the output of your existing filtration system to increase it's effectiveness.
Dispelling Some Myths-
Biological Filtration Killer-
U.V. sterilizers/clarifiers willnot kill beneficial biological bacteria in your tank. The basis for the biological filtration in your tank is within your filter and to a lesser extent your substrate,glass,ornaments and water column. The least amount of concentration being in the water column which is the only bacteria that can be destroyed by the U.V. as they are the only bacteria being passed through it's radiation. As such no matter how effective the UV sterilizer/clarifier is it should never effect your biological filtration detrimentally.
No more Algae-
No matter how effective the sterilizer/clarifier is it's incapable of filtering all your water at once. As such the sterilized water returned to the water column is constantly mixing with un-sterilized water and makes total sterilization impossible. So while it will slow proliferation of algae and generally keep your water clear it won't stop algae from growing in your tank all together.
No more Disease-
It's important to note a UV sterilizer no matter how effective does not rid a tank of disease. It merely kills most bacteria and viruses suspended in the water column. That means some will also survive in the water column and doesn't even consider what might be living within ornaments, substrate, glass or fish. Just as with algae it merely helps control the rate of proliferation and to an extent concentration of hazardous organisms in your tank's water column it does not eliminate them all.
**While I know this isn't a comprehensive description of U.V. sterilizers/clarifiers I do hope it's accurate and helps to give a basic understanding of them.
**As you may have noticed Redox is highlighted in green I did this to indicate I embedded a link in the word. If you click on the word you will be directed to link that more fully explains Redox. Here's a **couple of more links that you may find helpful and are just some of the sources of information I found regarding U.V. sterilizers/clarifiers. **
** Redox ** last updated 12/20/2012
** Ultraviolet Sterilization ** last updated 3/5/2012
** Fish Immune System and UV Sterilization ** last updated 9/6/2012
** UV Sterilizer Problems & Reviews; Ballasts, Submersible Pond, Killing Machine UVC Clarifiers ** last updated 2/4/2012
