UV sterilizer and water clarity not due to bacteria?

[HippieSmell]

I was under the impression that the increase in water clarity while using UV was due to the reduction of bacteria in the water column, but I just read that bacteria counts don't really fall while using using UV. Assuming that's true, why is the water clearing? Is it breaking down compounds that yellow the water? That's all I can think of.

 

[stephen13666]

I believe its killing free floating algae and spores.

 

[andtsg]

I believe is the Activate Carbon...

 

[slief]

UV filters kill free floating bacteria as well as oxidize organic compounds. The bacteria that we are primarily concerned with resides primarily in the Rock and substrate and not the water column. Thus, UV sterilzers have little to no impact on the important bacteria that we need to concern ourselves with. The typical increase in water clarity is the result of the oxidation of organic compounds that are in the water column. Those organic compounds often appear as small particles in the water column however smaller organic compounds also have an impact on the water clarity and the UV is helpful there as well. In the case of a bacterial bloom where waterborne bacteria is the water column, that is the one case where bacteria can cloud the water and in that case, UV will clear that up too.

 

[Fishbulb2]

Yeah, the low wavelength light will in fact break down some yellowing compounds. Though good practice is to have as clear as possible water entering the UV to get the maximum benefit for sterilizing purposes. So it's a bit circular. Use a filter sock and activated carbon to clear up the water as much as you can and the UV will be most effective. But the UV will also help itself by breaking down some organic compounds. Usually this requires a pretty hefty unit though. Ozone is more effective if the goal is solely to clear the water.

Are you fighting cloudy water? There can be many causes and an algae bloom is just one.

FB

 

[HippieSmell]

Yeah, the low wavelength light will in fact break down some yellowing compounds. Though good practice is to have as clear as possible water entering the UV to get the maximum benefit for sterilizing purposes. So it's a bit circular. Use a filter sock and activated carbon to clear up the water as much as you can and the UV will be most effective. But the UV will also help itself by breaking down some organic compounds. Usually this requires a pretty hefty unit though. Ozone is more effective if the goal is solely to clear the water.

Are you fighting cloudy water? There can be many causes and an algae bloom is just one.

FB

I've got a rollermat and an 80w UV, no carbon. The tank is cycling right now, so the water was quite yellow, as expected. It's dang clear now!

 

[Fishbulb2]

I see.

I had the darnedest experience with this new tank I set up. I set it up this summer and it has been incredibly cloudy ever since. I ran a diatom filter, used carbon, and do daily automated water changes. Nothing help at all. I walked in this afternoon after work and it was clear. Really strange, but I'll take it!


FB

 

[L8Braker]

Ozone also really helps with clarity FYI