Will a UV sterilizer kill Ich?

[glenns]

Will a UV sterilizer kill Ich? If so, how long should I leave it running to insure there will be no more outbreaks?

[Juruense]

Personally I consider UV sterilizers to be too gimmicky and would never ever consider buying one.

If anything I personally would occaisonally run a hang on tank diotamaceous earth filter to clean the water of algae and parasites. No bulb to replace and ALWAYS 100% effective.

[plateboy3293]

Uv sterilizer do kill ich but only in the free swimming state. I bought one at petsmart for 50.00 it was an 18 watt sterilizer

[chrisp074]

It may help control the parasite to some extent will will not effect a cure.

Chris

[glenns]

OK. It looks like I have to find somewhere else to keep my fish and corals and allow the tank to go fallow. I only have a problem when a fish becomes stressed.

[1DeR9_3Hy]

Yes, if it passes through the filter it will kill it. Like said above though, it only kills the free swimming ich. But since all ich has to go through the free swimming stage, it will cut down on the amount of ich swimming around looking for a host in the tank.

UV is far from "gimmicky", its been in use for atelast 20 years that i know of and i have first hand seen the difference a large UV system can have on a large system of aquriums. I do not see why a small uv system on a small system of tank(s) would change that.

[chrisp074]

<a href=showthread.php?s=&postid=13673492#post13673492 target=_blank>Originally posted</a> by glenns
OK. It looks like I have to find somewhere else to keep my fish and corals and allow the tank to go fallow. I only have a problem when a fish becomes stressed.

Corals can stay, Cryptocaryon irritans is unable to use them as a host.

[glenns]

I thought you also had to lower salinity to hypo levels and raise the temperature to kill off ich.

[chrisp074]

Not if there are no hosts for it, hypo/copper are used to treat the fish, which needs to be done in a hospital tank.

[glenns]

OK. Thanks.

[zrack4]

<a href=showthread.php?s=&postid=13673694#post13673694 target=_blank>Originally posted</a> by glenns
I thought you also had to lower salinity to hypo levels and raise the temperature to kill off ich.
Raising the Temp will speed up the lifecycle of ich.

[greenbean36191]

But since all ich has to go through the free swimming stage, it will cut down on the amount of ich swimming around looking for a host in the tank.
Beyond the inherent limitations of UV units on recirculating systems, the complex lifecycle of ich makes UV nearly useless for trying to reduce the parasite concentration. After it excysts from the substrate, the parasite actively searches out a host. From that point on, there are only 18 hours at most where the parasite will be vulnerable to the UV sterilizer. Most of the parasites that will infect have already done so well before that point. Any others will become non-infective. The only ones that will pass through the sterilizer are those that were tracking a fish and swam close enough to an overflow to get sucked in.

Tests of UV sterilizers on FW ich, which has a nearly identical lifecycle have shown that even with kill rates of 99.99% at the unit, there is no reduction of parasite numbers in a recirculating system.
UV is far from "gimmicky", its been in use for atelast 20 years that i know of and i have first hand seen the difference a large UV system can have on a large system of aquriums. I do not see why a small uv system on a small system of tank(s) would change that.
When used for parasite control on recirculating systems it's absolutely gimmicky.

It has been repeatedly shown to be ineffective at reducing either parasite loads or infection rates of pathogens in recirculating systems- from bacteria to protozoans. The key limitation is that the volume of sterilized water is always much less than the unsterilized water that dilutes it.

UV sterilizers themselves certainly aren't gimmicky though. They have been used for a long time as a very effective way to sterilize water in single-pass operations such as natural seawater being pumped in or out of an aquarium or water being pumped from one aquarium to another. The key there is that the sterilized water doesn't remix with the "dirty" water after it passes through.

They've also been used to generate minute amounts of ozone which can help clarify water, oxidize organic material, and induce spawning in some organisms.

[ERIKATHORNBURG]

I ran a UV unit on my old 75g reef. But, had advise from someone this time around in setting up my 120g reef to not use one. They said that it killed off good stuff too. So, I haven't bought one for my new system. I will be reading and watching for opinions on this subject.

[iamthereefguy]

UV should works if you do it right. The problem with folks that tried it and didn't have good luck with it because they didn't use strong enough bulb or not enough flow through the system or combination of both. I have a 36W UV. I never have ick on my fish after installing the UV.

[Urchinhead]

Actually UV Sterilizers are a method of controlling in the water column parasites and pathogens including algae and ich. The key is the hang time in front of the light. Longer being better. For example a 18w UV (most common) needs a flow rate of 60 gph to be effective against most parasites and pathogens. Anything faster and it won't do the job.

The problem with ich is that, as someone mentioned above, only part of its life cycle is free floating in the water column.

[greenbean36191]

The problem with folks that tried it and didn't have good luck with it because they didn't use strong enough bulb or not enough flow through the system or combination of both.
No. We're talking about controlled studies where the irradiance and dwell time are specifically designed to exceed the known lethal limit of the parasite in question. We're talking about 132 watt units that can produce in excess of 99.9% kill rates of protozoans even at 450 gph. These aren't the little toys hobbyists are playing with.

The issue is a fundamental problem with UV on recirculating systems. It's an issue of diminishing returns and with parasites, unavailability of what you're trying to kill. Even assuming a 100% kill at the unit and free-drifting parasites that are waterborne for the full lifecycle (assumptions that improve the impact of the unit), the maximum theoretical reduction in parasite concentration in a 250 gal aquarium with an 18 w unit running at 60 gph is about 5%. However, the reality is that multiple studies have shown that even when you use known lethal doses and measure better than 99.9% reductions at the unit, you don't even approach the theoretical limit and usually don't even get measurable reductions in parasites in the system.

Actually UV Sterilizers are a method of controlling in the water column parasites and pathogens including algae and ich.
Yes, in single pass setups, NOT recirculating systems. Algae is a bit different since the unit affects nutrients that fuel the algae as well as the spores.

[Juruense]

All I know is I ain't ever buying one...

[tmz]

Thanks Greenbean. Would appreciate your opinion on three questions.

BTW Still using uvs. Not sure why anymore.(total of 96watts on 300g display). After two years of use, it is my experience that they do not control crtptocaryon irritans.

Since you note algae is different would they have beneficial effect against the dinoflagellate velvet(amyloodinium) in a recirculating system?

Will equilibriation also offset losses of bacteria in the water column that would consume nutirents or will a uv depress these populations?

If I discontinued their use would I likely see a harmful rise in organics given the loss of the minute amounts of ozone?

[Urchinhead]

<a href=showthread.php?s=&postid=13676373#post13676373 target=_blank>Originally posted</a> by greenbean36191
[B]No. We're talking about controlled studies where the irradiance and dwell time are specifically designed to exceed the known lethal limit of the parasite in question. We're talking about 132 watt units that can produce in excess of 99.9% kill rates of protozoans even at 450 gph. These aren't the little toys hobbyists are playing with.


Yes. I know. I believe I have read the same ones you did.


The issue is a fundamental problem with UV on recirculating systems. It's an issue of diminishing returns and with parasites, unavailability of what you're trying to kill. Even assuming a 100% kill at the unit and free-drifting parasites that are waterborne for the full lifecycle (assumptions that improve the impact of the unit), the maximum theoretical reduction in parasite concentration in a 250 gal aquarium with an 18 w unit running at 60 gph is about 5%. However, the reality is that multiple studies have shown that even when you use known lethal doses and measure better than 99.9% reductions at the unit, you don't even approach the theoretical limit and usually don't even get measurable reductions in parasites in the system.


I didn't say it was the be all end all. What I said was that most people who utilize it do not do so correctly. I also should have been more clear. I mentioned that it worked only on parasites in the water column. What I should have done was expand on that as you did and discuss the number of parasites passing the unit.

Let me be clear. A UV Sterilizer will help with parasite control. It will provide N amount of reduction via modification of the parasite's DNA due to irradiation of said parasite from light at a wavelength of 254 nm in the total number of free floating parasites that pass the unit at S speed. The extent to which it will help is open to discussion and frankly will depend on the type of parasite, bacterium, and/or algae.

I say open to discussion because I am pretty confident that I would be able to go back and find studies that would both prove and disprove my statement that it is helpful in parasite control. I say that because when I was first researching the subject that is what I found.

A UV Sterilizer is not a substitute for proper quarantine and treatment of infected fish and an infected tank nor is it a substitute for control of the various factors that contribute to algae outbreak. What it will do is provide some amount of benefit (open to discussion) in parasite, bacterium, and algae control.

[tmz]

<a href=showthread.php?s=&postid=13673255#post13673255 target=_blank>Originally posted</a> by glenns
Will a UV sterilizer kill Ich? If so, how long should I leave it running to insure there will be no more outbreaks? :) A brief answer. I use several uvs and have for years and this is based on obsevation and reading.

Will a uv sterlizer kill ich?
Yes if it's big enough and ther is a sufficient exposure time to the radiation.

....how long should I leave it running to insure there will be no more outbreaks?

I run mine 24/7 and see no reason not to. You can not insure there will be no more outbreaks with a uv sterlilzer even an oversized one. It may or may not have some impact on density and virulence of the parasite at various times.

Overall the sterilizer is highly overatated for disease control in reciruclating systems,in my opinion.

[Roy G. Biv]

Maybe coincedence but every time I see ich, I turn on the UV and it gets better. I never counted how many ich I have so I dont know what percentage the UV kills :(