UV... any down sides???

[Endlersendlers]

I’ll add another thing - some people put the UV on a timer for a couple hours a day. UV can break down plastics with long term use, so maybe your media trays exposed to it might crack after 2 or 3 years if you have it on all the time. I leave mine on 24/7 and it’s been a year with no visible deterioration in the plastics.

 

[Endlersendlers]

To answer your other point, UV will kill bacteria in the water column, good or bad, but that’s ok because the bacteria in the substrate and in surfaces does most of the work. What’s floating in the water is inconsequential.

I’m not fighting algae in the substrate, although it’s growing on my Anubis and hair algae is trying to take hold on the floating plants. I rarely have to clean the glass and surface either, but I do also have a clean up crew. I think the UV is helping keep the algae population slow growing.

 

[Boundava]

The reason I asked is because a more likely scenario is that it wasn’t a suitable fitting for an aquarium and it released voltage into the water. I’ve not heard of Tidals having a UV attached?

it wasn't part of the tidal, it was a small enough UV sterilizer that we could put it in the tidal so that we didn't blind the fish.

 

[Wills]

it wasn't part of the tidal, it was a small enough UV sterilizer that we could put it in the tidal so that we didn't blind the fish.

Do you know what make or model it was? I've never seen something small enough to add into a filter, would be interested to check it out. They are usually in quite thick black boxes to stop the light escaping?

Wills

 

[Colin_T]

UV (ultra violet) sterilisers have been around the aquarium trade for over 50 years. They haven't changed much in design and are normally a plastic case that houses a UV globe. Water passes through the casing and is exposed to UV light. The UV light is separated from the water by a piece of glass.

The slower the water passes through the UV unit, the more time it spends exposed to the UV light and the more the UV light can kill off anything in the water. Filtering the water before putting it through a UV steriliser is the most effective way of treating the water because there will be fewer particles in the water to hold harmful pathogens. Basically clean water going into the UV unit will allow the UV light to kill more microscopic organisms in the water.

As Byron mentioned, unless you get all the aquarium water through the UV unit before it goes back into the tank, you aren't going to get rid of much because the clean UV treated water simply mixes with tank water that is contaminated. That doesn't mean they don't work, just they work slowly and only kill a small portion of harmful pathogens in the water. So they won't stop your fish getting sick if you have a disease outbreak, but they will slow the spread of the disease. As others have mentioned, big water changes can dilute diseases and green water in aquariums and that is usually cheaper than a UV steriliser.

UV steriliser units for aquariums need the globes to be changed regularly so if you get one, make sure it is easy to replace the globe and make sure the globe doesn't cost too much. There are some cheap UV units on the market but the replacement globes cost nearly as much as the unit.

As a way to reduce diseases in an aquarium, they can be helpful, but so can water changes and gravel cleaning the substrate.

 

[Endlersendlers]

UV (ultra violet) sterilisers have been around the aquarium trade for over 50 years. They haven't changed much in design and are normally a plastic case that houses a UV globe. Water passes through the casing and is exposed to UV light. The UV light is separated from the water by a piece of glass.

This is the type that worries me for people dropping it in the tank with the fish and blinding them, harming people who are exposed. Those who don’t know better may.

 

[Magnum Man]

Thank you all for the discussion thus far...

this was said previously...
"Perhaps a better title for this thread would be "any positives" rather than any downsides. In freshwater UV is so limited it is frankly useless. Green water can sometimes be improved with UV but it depends upon the severity."

it was my understanding, that it was most useful as a treatment for the parasite that causes Ich... maybe that was just propaganda posted by the UV makers???

 

[Endlersendlers]

Thank you all for the discussion thus far...

this was said previously...
"Perhaps a better title for this thread would be "any positives" rather than any downsides. In freshwater UV is so limited it is frankly useless. Green water can sometimes be improved with UV but it depends upon the severity."

it was my understanding, that it was most useful as a treatment for the parasite that causes Ich... maybe that was just propaganda posted by the UV makers???

I don’t think it’s propaganda. It kills what goes through and is exposed but it won’t kill ich in substrate or on new fish. Someone said it doesn’t help unless you put absolutely all the water through it. I disagree and that’s like saying filters and water changes don’t work unless they are 100%. These things decrease the particles, and hopefully the bacteria and virus load in the water and none are perfect, nor do you want them to be since you need good bacteria, but I know you already know that.

Water changes could be more effective by dilution, but UV keeps working in the background. Belts and suspenders perhaps. If you get green water despite other measures, the UV should clear it whereas the others just dilute it.

 

[Colin_T]

This is the type that worries me for people dropping it in the tank with the fish and blinding them, harming people who are exposed. Those who don’t know better may.
View attachment 321573

That is a concern and people should avoid using anything like that

 

[Wills]

This is the type that worries me for people dropping it in the tank with the fish and blinding them, harming people who are exposed. Those who don’t know better may.
View attachment 321573

Oh wow @Boundava is this the kind of thing you had? Not seen these before but I agree I wouldnt trust them...

The one I've been looking at is this one

A much bigger sealed unit that sits externally to the aquarium.

 

[BrianK]

This is the type that worries me for people dropping it in the tank with the fish and blinding them, harming people who are exposed. Those who don’t know better may.
View attachment 321573

That is the kind I have but I definitely do not put it in the tank. It is in the filter section of my AIO so there is a layer of black plastic between it and my fish.

And I should add, the instructions that came with it said not to put it in with the fish (if people actually read the instructions which I know is not a given).

 

[Byron]

it was my understanding, that it was most useful as a treatment for the parasite that causes Ich... maybe that was just propaganda posted by the UV makers???

No, it is not effective for ich or any other parasite. Note, I said effective, by which I mean it will not kill all of the parasites. And that is not of much help. More than 90% of all disease occurring in an aquarium is caused by stress to the fish, weakening them so they cannot normally deal with this and that. When you have a case of ich, by the time a UV gets even 1/1000th of the parasites, the fish will likely be near the end. It is not an effective treatment for ich or most anything else.

If you know the ich cycle, each cyst ruptures releasing dozens if not hundreeds of parasites. These must find a host within 24 hours or they die. I can guarantee that most of them will easily find a host fish long before they get anywhere near the UV. It is just common sense.

I disagree and that’s like saying filters and water changes don’t work unless they are 100%. These things decrease the particles, and hopefully the bacteria and virus load in the water and none are perfect, nor do you want them to be since you need good bacteria, but I know you already know that.

Water changes and filters are not the same thing. As I just typed in this post, the vast majority of nasties will easily bypass the UV because of the way it works. You will not reduce any pathogen or parasite by any relevant level with UV, unless you can move all the water from the aquarium through the UV to another aquarium. This should work.

My water authority here in Vancouver uses UV primary filtration. It works because the reservoir water passes through the UV and then through the system to the homes and such. This is crucial for UV to be effective.

 

[Wills]

You will not reduce any pathogen or parasite by any relevant level with UV, unless you can move all the water from the aquarium through the UV to another aquarium. This should work.

Would this mean that UV would be more effective in a sump situation? Or would the moment the water is passed back to the main tank mean its the same as if it were attached to a canister?

 

[Byron]

Would this mean that UV would be more effective in a sump situation? Or would the moment the water is passed back to the main tank mean its the same as if it were attached to a canister?

I can't say Wills, never used a sump. I would assume it is much the same problem though.

 

[Wills]

I can't say Wills, never used a sump. I would assume it is much the same problem though.

So when people use them on quite expensive set ups do you think its more of a placebo effect than doing any real benefit? I'm not looking for excuses not to do water changes - far from it - I've just always thought / hoped having UV would be in addition to the other standards of care you've mentioned?