Uv Filter Things...

[severina]

How well do they work? What all do they do? Can I get someone with experience with them to tell me a bit about them; the good and the bad? I like hearing from actual people than just reading all the little sales pitches on website online. Thanks

 

[Bignose]

They are good at killing near anything free-floating in the water, be that a parasite, algae, bacteria whatever. But, the thing has to flow through the chamber where it is exposed to the light -- in other words it will never be able to kill off 100% of the nasties in the water. It will increase the death rate, and the population will decrease until the birth rate and death rate are equal, but the population can never be reduced to exactly zero.

Other drawbacks are cost -- bulbs need to be replaced frequently as they stop producing the radiation they use after some time, the flow chamber has to be kept clean. There seems to be anecdotal evidence that the water can be too clean, that is the fish's immune system is weakened because everything in the water is killed off and the immune system stops working. I have my doubts about that statement, but it has been said.

To me, they are pretty unnecessary if you do the maintenance that you know you are supposed to do. I would consider them if you want to keep a particularly valuable, rare fish safer, but if you do all the things that have worked for fishkeepers for decades (quarantine, water changes, etc.), then they become little more than expensive toys.

 

[mantis147]

Ive got a TMC Vectron UV 8Watt, im no expert but i do know it keeps my water crystal clear it kills all the floating algae. The units are quite expensive to buy about £70, but the bulbs are only about £8 and need replacing every six months. But im happy with it!!

 

[karlp]

My LFS swears by them as a way of reducing outbreaks of parasitic and bacterial infections, but then they do have a lot of fish coming in and out of the store.

I've added one to my setup with my new tank because it's planted and I want to try to avoid putting meds into the planted tank as much as possible.

I would agree that if you follow strict quarantining, seperate nets, disinfect all your plants before putting them in the tank.. never feed fresh water live food, always remember the weekly water change etc... that they have limited value, but if you, like me, don't strictly follow these procedures rigidly, the UV can help to kill free-swimming parasites, bacteria and should help to reduce risk of disease in the tank or at least make it more manageable if it does happen.

It is correct though that if something like white spot breaks out, they generally wont cure it, just keep the numbers down, but white spot spreads at such a fast rate, that not all the parasites are drawn through the filter and killed by the UV before they get back to the fish.

I think it's a 'nice to have' item if you can afford it. The cost isn't that great, I paid £65 for the basic Vectron UV unit and then it's £7 every 6 months for a new bulb.

 

[trace1]

hi
i've got 1 on my 55 gal tank only cos the floating algea was that bad i couldn't see my fish & yes i do regular water changes, in fact that tank had a weeks worth of good water changes & it made no difference to the algea. after only a few days of having it in my tank the water was crystal clear. mine is a fish r fun with submersible with filtration pump & cost £60 lamp is 24w

 

[andywg]

All that UV does is destroy free floating life forms. This makes it the best treatment for Ich bar none.

I would say that if you keep a large tank with anything rare then they are essential. My UV on my 180 destroyed a fairly heavy Ich outbreak in a matter of days and it has never come back. If it didn't destroy all the Ich then there would still be signs of discomfort as to survive the ich must host on a fish every 3 to 4 days or so.

Do you have any evidence that it leaves a background population in the tank? I severely doubt this as the entire volume of the tank is flushed through the UV around 5-10 times an hour.

Bulb changes are not that bad...every 12 months.

 

[rdd1952]

It really depends on what you want it for. As mentioned, it will kill bacteria and will definitely clear green water. I have used one on 2 different tanks to clear the greenwater (diatoms) and it works like a charm. Here is a link to a thread I did with day by day pics of the 2nd tank I used it on. The first one was actually quicker but I didn't think to document it at the time. I'm pretty sure CFC runs them on his tanks inline with his canister filters and I'm sure there are others that do too. I just ran mine for the time needed using a water pump.

 

[fishing4exotics]

You need them more for bigger tanks and tanks that are exposed to a lot of light ( near a window ). I use them on my bigger tank. They do eliminate green water. I turn on the UV maybe a day every other week. To keep the water clear. As for the UV killing parasites you need to have a slower flow rate than you would if you were just using it for algae. Parasites need to be exposed to the UV light longer.

If you are going to use a UV for a small tank I would use it inline with a canister. I would attach it to the outlet of the canister. This way sludge doesn't build up to quickly on the inside of the UV unit.

 

[severina]

Wow! Thank you guys for all the replies!

I was treating one of my tanks for whitespot, and they did not respond to the medication I gave them and both of my oscars died. The other fish in the tank (2 cories, yes I know I need to buy more) are fine and were not affected by the white spot...so I'm going to break down the entire tank and start all over, and I want to put the cories in my bigger tank that just finished cycling. I'm scared the cories are going to infect my other tank. ALso when I was doing a water change on the white spot infected tank, and was carrying the water off, a little bit of the water splashed on my bigger tank, so I'm paranoid about that too.

Is it possible to only use the UV when there are problems such as these? I'm thinking that would cut down on costs, alot.

ETA: Bigger tank=55 gallon

 

[Rodders]

After initial cost it only costs £5-£10 every 6 months for a new tube. Thats 6 months full running.

 

[Bignose]

andywg, the evidence that is leave a background population is from the math. Remember the old thread we talked about this in? http/www.fishforums.net/index.php?showtopic=109233&hl=

It is a simple idea... the UV light is only exposed to a small percentage of the entire tank's volume at any time. Even if the flow rate is very high, the tank water remixes with the UV output. The entire concentration will go down, but it will never be zero because it gets remixed. You understand that even if the flow rate is 5-10 times the tank volume per hour that does not mean that every water molecule in the tank goes through the UV 5-10 times an hour, right? Some water goes through 100 times, some goes through 0 in any particular hour.

I agree that it can decimate populations quickly, but it alone can never get the population to zero, because the UV does not treat the entire tank at once.

 

[andywg]

But then nothing will treat the entire tank. No medication will touch every single water molecule. And why is there no sign of the Ich parasite still habiting the fish? For it to be present it must host on a fish every 3-4 days which means there would be some sign of it.

And I understand that not every water molecule will go through the filter that many times per hour, but I still want to see some evidence of there being Ich in a tank that is running UV before I believe pure maths over experience.

The chances are that the population reaches a small level that the fishes natural defence can overcome and therefore the parasite cannot gain a hold on the fish and as such will die before reproducing

 

[severina]

That makes sense, andy.

PS: Love weebl

 

[Bignose]

But then nothing will treat the entire tank. No medication will touch every single water molecule.

But a medication that you have mixed with the tank will touch every molecule. Assuming you have mixed it. The medication is everywhere in the tank, the concentration will become uniform because of mixing. On the other hand, if you have a UV in one part, and since it can only affect a small fraction of the tank, the entire tank cannot be uniform, cannot be perfectly mixed. This is simply what happens when only a small part of a tank is affected, and not the entire tank.

The chances are that the population reaches a small level that the fishes natural defence can overcome and therefore the parasite cannot gain a hold on the fish and as such will die before reproducing

Ah, but then the fish are also affecting the ich population. I have repeatedly said that UV alone cannot take care of any problem, but other circumstances must be accoutned for as well. Also, you know that a small asymptomatic population can exist... a single ich can live on a fish and said fish will not show flashing, and you may not see that spot. Especially is the spot is small, or in a gill.

Fish can fight off a small enough popoulation on their own due to their immune systems, if you can get the population small enough, maybe then the fish can fight off the rest. That said, the UV alone cannot do it, it is physically impossible.

 

[Bignose]

Here is some more information from a scientific journal. "Ultraviolet light control of Ichthyophthirius multifiliis in a closed fish culture recirculation system" by Gratzek, Gilbert, Lohr, Shotts, and Brown. It was in Journal of Fish Diseases volume 6, pages 145-153, 1983.

They found that while UV could prevent the spread of Ich when used on a central system, it could not affect a cure within an individual aquarium. Which is exactly what I said above... UV alone cannot cure a tank.