Bacterial outbreaks occur CONSTANTLY. A fish tank is a medium for microbiota with a large volume of biotic potential - meaning it has everything and more to grow and support large colonies microbiota.
UV radiation is undoubtedly a smart route to go 24/7 in your tank to control pathogenicity and water clarity. I have a large back round in microbiology, organic chemistry, physiology, and much more that help me in my quest for water quality. I know of some aquatic professionals who specialize in koi ponds that wont go without using UV.
UV rays are a great way to stop disease in fish tanks FACT.
I have a question for those UV users out there. Right now I have an in-line heater on the return line from my canister filter. Would you add a UV filter after the heater or would there be too much return line flow restriction? I like the idea of an in-line UV but am not sure how to implement one with the in-line heater.
I'm of the opinion that you can never have too much filtration.
No, it doesn't. Assuming that your bulb is replaced every 6-12 months and your wattage and flow rate are properly aligned to give you at least the minimal exposure time(otherwise you are accomplishing nothing), you might have 99% kill rate of water passing through the UV filter on nay given pass. But that water doesn't pass through once like in sewage treatment, it immediately mixes again with tank water so the next batch through is not 100% new water, and, in principle, some tank water never gets through. So you can't even kill all the free-floating micro-organisms, let alone those that are affixed to the tank, fixtures, etc. Does UV help beat back problem outbreaks? Yes, assuming the bulb is new and the flow is below the max recommended. But does it even come close to eliminating pathogens? Not even. Also, for every watt of UV used, it's like adding that many watts in a heater, which can be a good thing in a discus tank.
???
Where in the world did that come from ? What do you have to back that up ? Sounds like gobbledy-goop to me.
Do you have any experience at all using a UV sterilizer ? Do you completely discount the manufacturer's claims, which have undergone many serious clinical tests ?
7 posts ? sounds like a "pro" to me ?
Please don't attack me personally; it is not right regardless of whether you know me or how many posts I have (everyone is new at one time). I'm just here to acquire knowledge, and share it where I have it. I have seen many helpful posts from you here Paul, so I am surprised to catch this from you, simply because I disagreed with you. [end flame defense]
If you don't agree with some specific part of my post, please say so, and we can discuss the facts. Fact: UV bulbs can only kill what they see, which is in the mechanically filtered water passing through the unit, not water in the tank, although most tank water does eventually pass through the unit, but never all, and the nasties are reproducing exponentially as you approach the asymptote anyway. A good water change regime probably removes more free-floating micro-organisms than UV (granted, speculation there). AND they only kill if they are given sufficient time to do so, which means slow enough flow past the bulb for their given wattage with the time req specific to the type of micro-organism, i.e., some are less sensitive than others. If you exceed the max flow rate, you do not get sufficient exposure and an effective kill. UV filters will knock back but not eliminate free-floating micro-organisms; nothing is 100% and no reasonable manufacturer would claim as much. And they simply cannot touch affixed micro-organisms, which do not flow with the water through the UV unit; the photons stay in the unit! I will hold any manufacturer's claims against those facts.
Water changes are necessary for Discus health. How much and how often is open to debate. UV does kill bacteria and algae and it is a good addition to water changes. UV is certainly beneficial, how beneficial I do not know. Will UV cure sick fish, usually not. Will UV help cure sick fish, probably yes. As far as BB, they are mostly in your filter medium. If BB come out of your filter the UV will kill them also. I am not a microbiologist, but it is common sense that some BB come out of your filter regularly as ther water passes thru. How much BB comes out I do not know but the filter still works with this, I think, small loss of BB. By the way the bacteria are called gram negative because they absorb a standard stain used in microbiology and the called "Gram Stain" that helps to identify the bacteria under a microscope. The bacteria cell wall turns blue or pink from the stain, I do not remember which color is positive or negative but if you are curious try GOOGLE. I think the gram stain attaches to a protein in the cell wall of bacteria.
Last edited by Elliots; 08-01-2012 at 08:44 AM.
Isn't the answer somewhere in the middle....
UV correctly fitted will kill free floating bacteria, algae, fluke/parasites if it pass through it.
But it won't kill everything in the tank just like a filter won't filter every bit of debris even in a BB tank.
So if the argument is that in a well maintained BB tank + large daily water changes will make UV less effective then yes a valid argument.
But much like some feed home made beef heart, because it gives the Discus that extra margin of health benefit, having UV + doing daily water changes will help lower what ever baddies that is missed, giving it that extra margin of safety.
Just my 2 cents
Totally agree (with TheDrake). Calibrating flow rate with UV is crucial. On a related point UV steriliser units are best positioned on the outflow side of a filter so that bacteria, or pathogens, cannot 'hide' behind the 'shadows' of debris that would flow through the unit if it was not filtered prior to entering the unit. There are obvious advantages commonly cited with using UV units but a possible downside is that fish raised in such conditiones may not build up 'disease' resistance and can suffer when transfered to a 'normal' environment. BTW I do have experience of this . . .
On the point of how many posts a person makes: IMO it is the quality of the posts submitted that is a more important consideration than the quantity of post made by a member.
I am always somewhat amazed with the absolute certainty that many people state their "opinion" without even attempting to site an actual study that was done to support their "opinion." Point me to the study that shows that using a uv sterilizer has no benefit and I will consider it. Even if there is only a small benefit to using one, it appears to be worth the cost, in my humble opinion. Especially when you consider I bought one that is in my canister filter, a filter that I would be running anyway, and the whole setup cost my about $80.00 on e-bay. So if you have determined that it is not worth the cost to you, I respect that, but please respect others peoples right to come to their own conclusion after they have considered the facts for themselves.
I wish people would use the "search" capabilities of this website before asking the same question asked tons of times before. This thread wouldnt even have been started
Sent from my DROIDX using Tapatalk 2
I would have thought it more helpful if perhaps you had posted a link for the member who started the thread to follow - surely we should encourage (rather than discourage) members to actively contribute to the forum? The member may or may not have tried to use the "search" function for all we know. If indeed he had tried to seach: "UV filteration" I'm afraid the results wouldn't have been very "productive"...
Hopefully, this member will have gained some insight into UV filteration by starting this thread and reading the constructive, and varied, responses to his initial question?
BTW there are two types of UV units:
1. Those units sold for ponds which, are intended for algea / green water control. Water passes through a wide sleeve surrounding the UV lamp.
2. Units sold for aquaria that have a narrower sleeve around the UV lamp for use controlling bacteria / pathogens.
Last edited by Tommo; 08-10-2012 at 03:00 AM. Reason: BTW
As stated above in different posts the UV unit must be properly sized and the correct flow rate must be calculated as well as the desired Zap Dosage needed to kill the target organism. Bacteria such as Bacillus Anthracis need a Zap Dosage,(calculated in microwatt-Sec/cm2), of 8,700 to be killed and bacteria such as Sarcina Lutea need a Zap Dosage of 26,400. Protozoa such as Parmeium requires a Zap Dosage of 200,000 where Nematode eggs need a Zap Dosage of 92,000. Fungi needs a Zap Dosage of 45,000
It is true you can never have all the water in a tank completely sterilized at any given moment because, as stated in a previous post you are adding filtered water to contaminated or water which has not been filtered. The sterilizer is removing bacteria, parasites, etc at a slow rate and the purified water is being returned to un-sterilized water and then that mixture again goes through the sterilizer and so forth. So we need to know how many hours the sterilizer needs to run so the water is sterilized to a desired percentage. The answer is T=a(G/F) where T= Hours of sterilization required. G= Gallons in Tank. F=Sterilizer Flow Rating (GPH). a= Purity coefficient. If you had 99% of the water in a 100 gallon tank which was sterilized you would still have 1 gallon which was not. However you can achieve 99.99 percent of a given body of water which is purified or higher percentage. 99.99% of 100 gallons leaves 1.28 ounces of unpurified water.
So how many hours will it take for all the water in a 50 gallon tank to pass through a aquarium device when the flow rate is 60 gallons per hour? The purity coefficient used will be 9.2 which is directly related to 99.99% T=9.2 (G/F)=9.2X50/60=7.66 hours. So about three cycles of the tank's capacity is needed per 24 hour period.
By using a low cost flow meter and a by-pass line after the pump a desired flow rate can easily be achived.
Most of you know I am not smart enough or educated enough to come up with the above. I use a great book, long out of print but it can be found on eBay and Amazon sometimes. Aquatic Systems Engineering: Devices and How They Function by P.R Escobal.
Escobal worked for Rocketdyne, where he worked on the F-1 motors which were used to propel man to the moon to list just one of many of his credentials. He and his wife founded Aquatronics in 1969 and Filtronics in 1971.
Kraig