Uv Sterilisers

[bodge99]

Hello all.

Sorry, but you **cannot** say that UV will not kill all ich in a tank. All you can say is that it **may** not.

There is some quite heavy calculus involved in UV power calculations for a given tank volume. It's all about diminishing returns... a suitable setup **will** treat a figure approaching (but never quite reaching) 100% of the water in a tank in a given time period.

The point is, if you use UV, the chances of a problem occuring and becoming serious enough to require medication is greatly reduced.

Surely preventing a problem in the first place is better than attempting a cure which may or may not work totally effectively, or without other side effects? After all, ich is not by any means the only problem that occurs... is it?

Bodge99

 

[hillmar77]

Other then Ich, it can also help out in alot of other deseases like fish lice, bacterial diseases, flukes, and other small parasites. It cant help the fish that it is infected but in most cases it can contain the spread of the disease and there numbers. I knew this was gonna be a pretty hard debate!

 

[Twinklecaz]

Hello again.

Twinklecaz:
At a minimum I would now fully strip your tank down and sterilise **everything**.

Yeah and cycle all over again wouldn't I. That's the thing . Also I still have another 17 fish in my tank with *touch wood* no probs. One of my Platys had a touch of body rot from scraping himself which is now all but gone and the Neons had a very mild dose of Ich when I got them which I also sucessfully treated. The problem seems to be just the Honey Gouramis which is why I think it might be Gourami disease.

Would sterilising really be the one way to get it out? I know that's true for NTD and fish TB.

 

[bodge99]

Hello,

Twinklecaz: At the end of the day it's your call as to how you want to proceed. Your particular bacteria problem may or may not cause future problems for your other stock. The presence of this bacterium may or may not rule out your future ability to be able to keep Gouramis at all without some sort of remedial action. As the exact bacterium type is unknown, you don't know how it is likely to survive within your particular tank setup. I've no personal experience of Gouramis and any specific infection risk that this genus is susceptable to. Others on this site may have more direct experience with this specific type of problem and may be able to advise you accordingly.

I have lost a full tank of stock due to an overwhelming bacterial infection. This was a few years ago in my "pre UV" days. My clearest memory of this incident was the anguish I went through trying to treat the problem and watching fish suffering and dying. It was a horrible experience that I **never** want to go through again.

I think your options are:

Do nothing.. and hope.

Try and treat the tank with anti-bacterial meds. You will probably have some sort of side effects.. loss of some beneficial bacteria for a start.

"Bite the bullet" and assume that everything is contaminated. Rehome your fish in another tank (borrow or buy something cheap secondhand if you can). Fully strip your tank and wash everything in a dilute bleach solution. Follow this with a rinse with a strong salt solution. Now rinse everything very well with plenty of clean water and leave to air dry. This last part is as important as the others so don't skimp on it. I'd replace any filter foams and carbon (if you use it). Ceramic rings can be boiled if required. Don't forget to clean any pipework, jugs, nets etc.

You can now rebuild your tank and start to cycle it. The method that you use is entirely up to you.. If you choose to use fish-in cycling, then try to use the hardiest stock that you've got. I do understand that you may have to return all of your stock asap if your emergency holding "tank" is sub-optimal. If this has to happen, then be paranoid about testing your water for a few weeks.. Be prepared for regular partial water changes so that the nitrite and ammonia levels are kept low.

This may be a good time to at least consider a UV steriliser.

Good luck and best wishes.

Bodge99.

 

[Twinklecaz]

Ha I think it is a good time. I've been looking at some today and notice you can get internal ones that seem to function as a second internal filter would. The only trouble is they all seem too big for my tank.

You can get external with built in UV's can't you? I'm wondering if that's the way forward for me aws I've been thinking of getting an external anyway.

 

[bodge99]

Hello,

External filters with built in UV are certainly worth considering. The ones I've seen tend to have lower UV power than some of the separate units. I personally prefer to use the largest power I can for my budget at the time of purchase. I'm sure that you will notice the beneficial effects of any unit however small, but for the sake of a little extra you can get a more powerful setup. As with everything, money is often the deciding factor.

Good luck with whatever you decide to go with.

Bodge99.

 

[Bignose]

Sorry, but you **cannot** say that UV will not kill all ich in a tank. All you can say is that it **may** not.

I absolutely can. Because it doesn't treat the entire tank at once! I know the "heavy calculus", and in fact have done the sterilizing problem. Both from the continuous point of view, and then from the stochastic point of view. The stochastic point of view takes into account the probabilities when there are very low numbers of organisms. In both cases, it is impossible to say that a population is 100% killed off. You can put a probability on complete kill off, but it will never ever ever be 100%.

Surely preventing a problem in the first place is better than attempting a cure which may or may not work totally effectively, or without other side effects? After all, ich is not by any means the only problem that occurs... is it?

Hence the quarantine tank.

 

[bodge99]

Hello,

Err, sorry but you can't. I too have done the math on this one and know exactly where you are coming from. A probability of any particular event is just that, a probability. It may or may not happen. Physics will tell you that a room full of smoke (partial replacement in a similar way to what we are discussing) will never be totally cleared of smoke when a window is opened. If you perform the calculations regarding the amount of smoke left in that room, then you will eventually reach the point where a fraction of a smoke particle is left in the room. In the real world this is nonsense. What counts is when any residue is insignificant.

Looking at your ich example. At any given time there will be a finite number of these parasites in our hypothetical tank. If a steriliser can kill a fixed percentage (assuming an ideal tank with even distribution of parasites etc. etc.) per hour then simple math will give an indication of when a figure of 99.99999% will be killed. Of course this totally bogus calculation ignores real world parameters. Ich may not be evenly distributed within the tank. If it happens that all of the free parasites are caught up in the water stream leaving the tank then they will either be trapped in the filter or killed in the steriliser. In any case, they cannot return to the tank to attack any host.

Any ich remaining have a calculable probability of being killed within a given time frame. This figure increases, approaching totatility given enough time. All anyone can say for certain is that our ich population may be wiped out.. or it may not. Which answer is correct in a specific case is open to speculation.

I think it is reasonable to say that the use of UV has a far greater chance of stopping this type of problem in its tracks before it develops. I still believe that preventing or reducing the chances of a problem developing in the first place is far better than having to undergo remedial procedures.

You obviously don't believe that the use of UV is "for you". Fine, I've absolutely no problem with this point of view at all.
What I do feel strongly about is certain sweeping statements I've seen e.g. That UV use is ineffectual, a waste of money or "snake oil".

Repeating what I've said in other posts (and 30 or so people that I've talked to about this agree), We have had no fish or tank health problems whatsoever since we started using UV.

Bodge99

 

[Bignose]

1)You are missing the fact that Ich (and any other parasite) reproduces at a finite rate.

This is a balance equation. dc/dt = B - D. c = concentration of the population. dc/dt = rate of change of population. B = rate of births, which will be a function of c. D = rate of deaths, which will be a function of c and a function of how much water goes through the UV and the UV's effectiveness. (As an aside, unless you have a micron filter, ich is far too small to be trapped in a filter.)

A UV can increase D significantly, I have not argued that it can't. But, eventually dc/dt will be zero, when B = D. That will occur at a non-zero c.

It is not like opening a window in a smokey room, which unless something is burning, there is no source for smoke. If there was a source for smoke, it too would steady state at a non-zero value.

Unless you treat the entire tank, c will not ever be zero.

2) Please don't misquote me. I never anywhere said "ineffectual" or "snake oil".

I have not misquoted you anywhere in this thread.

Nor did I say that using a UV would lead to problems.

Let me also say that I've never used a UV, and I've never had any problems either.

Saying that you've used a UV and that you haven't had any health problems isn't actually evidence to support the case. It is at best anecdote, and it specious logic to cite it. I also carry a medallion shaped keyring in my pocket everywhere I go and never been attacked by a sloth. By your logic, my keyring must prevent sloth attacks, right?

The best evidence would be to show that the costs of a UV and the associated decrease in cost in medications and new stock (if they passed) compared with the initial cost of the UV and the upkeep costs of bulbs and electricity balance in the UV's favor. To be fair, it would need to be in a control group versus my opinion that a quarantine tank prevents just as many diseases as the UV does. A q-tank is exceptionally cheap. A small sponge filter, a heater, and a plastic tub is really all it needs to be. This would be a fair comparison.

I suspect that no one has ever done this experiment. So, we will have to leave it to opinions.

I have never argued in this thread or any other that a UV doesn't do what it does. It decimates populations. But the birth-death equation is very clear -- it will never steady state at zero, which means that there is always a non-zero chance that a tank still has the parasite. Compare this to medication in which you CAN say that there is a zero chance of any population left. I'll take a zero chance to a finite chance any day. The best of both worlds is probably to have a UV in the cabinet ready for use when an emergency breaks out to quickly attack a population, and then remove the UV and use medication to ensure the 0%. With a decimated population, you probably won't have to medicate as long.

 

[karin]

P.S. My uv sterilizer was running when a fish that I bought introduced ich into the tank. I think it was a mild infection as no fish died but I also treated the tank... anyway, trying to say the UV sterilizer did not prevent ich in my case.

 

[bodge99]

Bignose: Yes, you are totally correct with the math. I was assuming a finite population.. I did say it was hypothetical! Perhaps I should have stated the criteria more accurately.

I **did not** misquote you. I do not attribute these comments to you. All I said was that I object to certain sweeping statements that I had seen.

I think the whole debate indicates that real world systems perhaps cannot be modelled with 100% accuracy.
I do understand what the math indicates, it's just that in the real world nothing is totally certain. A certain treatment may or may not be totally effective.

I am not trying to upset anyone with my views at all and I do try to qualify everything that I say. Everything else is my opinion only.

At the end of the day I can only state one thing with total certainty. I have had no fish or tank health problems whatsoever since I started using UV. Other peoples experiences will vary. That's life!

Bodge99

 

[Bignose]

...indicates that real world systems perhaps cannot be modelled with 100% accuracy.

Every scientist in the world just cried a little.

As far as models go, this one is pretty simple, really, and pretty accurate. It isn't as complex as turbulent flow, or the processes inside the sun or something really complex.

One can create pretty constitutive equations -- the birth rate of ich is known as a function of temperature, for example. The death rate is a function of the concentration in the tank and the rate at which the UV treats the water. The assumption of a perfectly mixed tank is pretty good really. The filter return and intake does a pretty good job of mixing, not to mention the fish themselves. Sure, it isn't 100%, but in terms of the math, it is pretty good.

Nevertheless, if we understand the model, we can still garner useful information from it. Same as there isn't a 100% model of the sun or of turbulent fluid flow, yet we still get useful information from those models, too.

 

[bodge99]

Err.. I think that you actually agreed with my point here.. A model of any system is by definition an approximation. Yes, useful information can be gleaned for what the math spits out, but one must always remember that any process involving probability functions (most, if not all of the universe in some repect) essentially means that little is totally certain when approaching the limits of that model.

I have always believed in the scientific method. It is obvious to me that you do too. I do understand that we live in a chaotic (math/physics definition) universe and our nice, neat models of any particular system, however near accurate will **not** cover every variation in reality.

This is why I question such statements as "UV will not kill all ich in a tank". Just because the math says so does not mean that this statement is true in **every** case. All I have ever said is that it may not.

The other thing I would like to mention is regarding this:

"Saying that you've used a UV and that you haven't had any health problems isn't actually evidence to support the case. It is at best anecdote, and it specious logic to cite it. I also carry a medallion shaped keyring in my pocket everywhere I go and never been attacked by a sloth. By your logic, my keyring must prevent sloth attacks, right?"

Stating that I have had no fish or tank health problems since I started using UV was not meant to be "evidence to support the case".
All I was stating was that this was the **only** thing I could be totally certain of. You (and others) seem to be saying that, just because the math said so, UV **couldn't** clear all ich in a tank. All I have ever said is that it **may**.

I have never **ever** said that UV **must** be used to keep one's tank healthy. I have also **never** said that UV would, could or should replace medication in any way, shape or form.

All I have ever said is that I am **totally** convinced as to the benefits of UV. It is one of the major weapons in my warchest.

Bodge99