# UV Filter - What does it do exactly?



## Aeropars (Apr 20, 2006)

Hi guys,

I know UV dilters are good for preventing Diatoms but what else do they do?

Are they good at preventing other types of algae?

Also, it says they help with water clarity but how does it do this?

Thanks in advance,

Lee


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## Tonka (Mar 20, 2004)

UV light kills bacteria and some free-floating algae, and if strong enough, fish parasites too. The clarity improvement of using the UV for a few days is remarkable. It's most useful to control white bacterial blooms and green algae. I only use mine about once a month, but I wouldn't do without it.


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## Aeropars (Apr 20, 2006)

And i presuem you simply rin the water through it with a pump?

I'm thinking of on for m coldwater tank which is infested with diatoms although getting under controll with the algae eaters.

Just thought it might be a goot idea as well on the tropical tank. 

I have a 180 liter tank so what power woudl I need?


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## Tonka (Mar 20, 2004)

Mine is plumbed downstream from my canister filter. If you're going to buy a unit, you might as well have the cabability to kill parasites. 18W should be sufficient.


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## jeff5614 (Feb 15, 2006)

Tonka said:


> Mine is plumbed downstream from my canister filter. If you're going to buy a unit, you might as well have the cabability to kill parasites. 18W should be sufficient.


Agreed. I have a 25 watt on my tank. I felt if I was going to have one I wanted to be able to control parasites also.


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## yxberia (Apr 19, 2005)

I doubt UV could kill diatoms, as in most of my cases it didn't. UV kill free floating bacteria, algae spores (green water, black beard algae), etc. But It does not prevent dust & spot algae from spreading.

It couldn't kill existing in-vivo parasites but it could prevent them from spreading to other fishes. UV 11 watt and above is effective.


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## Squawkbert (Jan 3, 2007)

UV *can* be effective if it is properly designed & implemented - too much absorbance from a cheap (non quartz) sleeve, too high a flow rate past it, old bulb... can greatly diminish its effectiveness.

I would go for an ozone generator before a UV device. Clean probes annually, let it rip.


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