Instead Of A Quarantine Tank I’ll Use A UV Sterilizer

This to a newcomer seems like a good idea, applying some extra protection equipment to the display aquarium and avoiding the need for a separate tank with the consequent need for extra heating, power heads and the like. Closer examination seems to be in order.

What is a quarantine tank? This is a smaller aquarium that is kept in addition to the display aquarium. Its purpose is to welcome new fish additions (and corals etc  in many cases). The new arrivals are kept in quarantine for a minimum of two weeks, better four, so that any problems caused by the stress of transportation etc come to the surface and can be treated in isolation. If certain diseases raise their unwanted heads, then copper for example can be used, whereas in a reef aquarium it cannot as it is deadly to corals. In other words, newcomers are kept in isolation so that existing inhabitants of the display aquarium are not exposed to problems that could exist. Once the quarantine period is over and the aquarist is satisfied that all is well, the newcomers can be transferred to the display aquarium and the danger of problems is minimized.

The UV (ultraviolet) sterilizer is a piece of equipment that, as the name implies, helps to eradicate undesirable live content in the water – let’s just call the undesirables ‘nasties’. These could be bacteria or the spores of disease, mainly of the commonly called ‘white spot’ and ‘velvet’. What happens is that the water is pumped through the sterilizer, which is usually cylindrical. There is an outer wall and an inner one which contains the light, between is a thin gap. As the water moves through this gap life is exposed to the radiation and killed, or damaged to an extent that the ability to reproduce is severely impaired. It is very important that the water is pumped at the correct speed through the sterilizer so that there is sufficient exposure to the radiation, so the manufacturer’s recommendations need to be followed. It is also important that the given life of the UV bulb is not exceeded or the effectiveness of the unit will be reduced. Finally, the sterilizer should be sized to the gallonage it has to deal with.

So on the face of it the sterilizer could replace the quarantine tank (QT). It does exactly what is required, that is it destroys or damages unwanted nasties in the water. So there isn’t a need to keep fish in a QT as any nasties will be destroyed anyway. If only it was as simple as that, but it isn’t.

For the water to be pumped through the sterilizer there obviously has to be an intake. Logically the intake needs to be in an area where most water is likely to pass, so it needs to be where there is considerable circulation. So far, so good. Does this actually mean all nasties in the water will be sucked in and destroyed? Unfortunately it doesn’t.

In most modern aquaria, particularly reefs but also fish only, there is considerable decoration such as rocks or their substitues. This means that water will have quiet spots behind and under rocks or even just close to rocks. The method of reproduction of certain nasties is quite sneaky. They attach to fish where an aquarist can hopefully see them, then they drop off and go down into rocks etc. They then reproduce by division and where there were only a few there are soon many more. In the confines of an aquarium there can soon be high and increasing numbers. The point is that it is very likely that quite a lot of these nasties are going to be drawn into the steralizer, but not all. The ones left will reproduce and the problem can increase despite the presence of the sterilizer.

There has to be a QT then? The answer is yes, but there are considerable numbers of aquarists who seem to rely on luck and perhaps good judgement. The good judgement is choosing the source of their livestock and noting the condition of it, and the luck is that they were, well, lucky. By placing new fish straight into a display aquarium they are putting at risk the health of the livestock already there. Nowadays with better transport facilities and more knowledgeable dealers livestock should be in better condition, but there isn’t any guarantee of this, the danger of problems is ever present. There should be a period when a QT is put to use.

So the UV sterilizer is a waste of money then? No it isn’t, but it isn’t an essential either. The protein skimmer is viewed as an important assistant to the maintenance of high quality water. The sterilizer should be viewed in a similar way but with regard to health. The sterilizer is lower down the list of importance than a protein skimmer.

There isn’t any reason why a sterilizer shouldn’t be used if desired. It will help to destroy unwanted nasties and maintain health, or assist in the battle against existing disease. However, it is an aid to a healthy aquarium environment, not a guarantee of it.

If the aquarist maintains high quality water, provides a good diet and doesn’t overstock then there is a good chance of continuing good health. A UV sterilizer could be an aid but is not an essential as is for example a protein skimmer. If a QT is also used the potential for ongoing health is greatly enhanced.

  1. this post is very usefull thx!

  2. Always pleasing to know.

  3. Excellent points.
    Your comparison to a Protein skimmer is one I make often, as both provide similar benefits but are not 100% necessary.

    I should also point out that much research has shown that UV Sterilizers benefit fish via a more balanced Redox resulting in improved immunity.

  4. Really nice post,thank you, best website ever

  5. Thanks for that information,UV Sterilizer Director, good to know.

  6. Thanks Maria.

  7. Terrific work! This is the type of information that should be shared around the web. Shame on the search engines for not positioning this post higher!

  8. Thanks for the compliment CNA Training.

  9. This is such a great resource that you are providing and you give it away for free. I enjoy seeing websites that understand the value of providing a prime resource for free. I truly loved reading your post. Thanks!

  10. The target of this website is to help. I’m so pleased that it appears to be achieving the aim.

  11. I love the information on your blog! One of our local shops has a great Q and A section on there site. The Fish Doctor knows what he’s doing and offers well researched answers. The thing I like best is that he doesn’t make you feel stupid like they do on many forums when you ask a question. Check it out:

  12. Hello CJ. I’m in favour of anything that positively helps the marine aquarist. Thanks for your comment.

  13. Thanks for giving valuable information for UV sterilizer.

  14. This is an amazing idea! Applying a UV sterilizer will protect your aquarium better and has many more benefits.

  15. This is something I plan on experimenting with on my new 75 gallon I will be setting up over the next few weeks.

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