Will a UV sterilizer kill ich?
 

Will UV sterilizer make ich go away?

Thanks,

This question has been answered many times.

UV sized in general to kill waterborne bacteria and viruses is not strong enough to have a significant impact on ich.

A UV that is strong enough against ich would likely be strong enough to overheat a tank in the summer without a chiller.

I always use UV to reduce the incidents of bacterial and viral infection during eradication of ich, but not that UV has impact on ich.

BTW, UV degrades many drugs.

UV has a limited but still essential role in disease control if your interest includes many fish, even in/for a reef tank.

The diatom filter when properly charged with diatom earth is effective in filtering out most waterborne ich organisms. So it is effective in reducing the spread of ich, as it simulates the dilution effect of the ocean.

The diatom earth will have to be changed about weekly and the unit uses a lot of energy. It is good for brief uses only.


There is no practical alternative to eradication of ich by QT all fish and external/unknown sources of water. Eradication of ich is also quite doable and not difficult.

Thanks alot wooden.

UV sterilizers do work. Here is a difference of opinion between wood and I. A properly sized UV should be about half your gallons of water so if you have a 100 gallon tank you will want a 50 watt uv. Not only is the size important but so is the water flow rate. After several years of trial and error I suggest you properly QT and treat all fish an you should never have to worry about ich.

A UV, no matter how big, is only really good for multiple tank systems to keep ich from going from one tank to another (such as in a wholesalers setup.) The ich has to travel through the UV for the appropriate time to kill it. Properly setup UV will reduce amount of ich, but will not get rid of it as all of the ich will not go through the UV before infecting a fish. Better off with Hypo or copper.

I think you do not need quite as large a uv to kill most waterborne bacteria in most situations.

I go by about 10 gph per watt for a turnover of just 1 or 2 in DT.

If you have only one uv sized for DT, when you use it in QT likely you will have a greater turnover.

I find an 8 watt unit in a 30 gal QT effective in reducing incidents of external bacteria infection.

One subject of interest is the quartz sleeve. I think units with it is more effective per watt. I am not sure anymore, but long time ago I read that the purpose of the quartz sleeve is to reduce heat transfer to the water. A hotter UV bulb gives more UV than a cooler one. The temp of the bulb has an effect on the wavelength distribution of the light given out. I am not sure about the science behind it. May be someone else is.

I think most UV makers overstate the ideal flow rate. May be stating the ideal flow to kill bacteria seems too slow and hurts sales.

Won't kill the ich on the fish.... plus makes copper toxic, but copper kills ich ;)

Just use an effective treatment like copper or hypo to kill ich.

A UV unit in the way it is used without tank transfer can be good in reducing the waterborne concentration of a patheogen, be it ich or bacteria. Even if a very powerful uv is used against ich, this will still be true.

I believe the effectiveness of having very low concentration of waterborne ich and bacteria by UV for many weeks are also quite different.

A very low concentration of waterborne bacteria may well help a fish in developing effective antibodies later. There may well be just enough exposure to the bacteria without overwheming the general defense of the fish, very effective antibodies would result almost independent on later patheogen concentration. (And water concentration of bacteria has to be low due to herd immunity.)

Whatever defense a fish has against ich is far less reliable and more dependent on later concentration of ich. Ich infestation is more a phenonenon of confinement than a disease. Bacterial infection is a disease even in the ocean.

Against bacterial infection, effective immunity of fish would eventually be achieved after UV ceases. Not so for ich.

Does UV make copper more toxic?

I have never had problem with straight copper when using UV.

Would UV affect cheleted copper?

I have not used a cheleted copper for over 25 years so I can't say for sure.

The use of the UV during eradication of ich is to reduce the chance of bacterial infection during treatment against ich, when stocking new fish per se.