How is good is UV light for preventing algae?

Hey Guys,

How is good is UV light for preventing algae? Will it have any other consequences like decreasing my beneficial bacteria count.

I am planning on having a submersible UV light filter in my DT.

 

UV light (also known as a UV filter, if run in-line with your sump plumbing) is primarily used in saltwater tanks, not so much for preventing just algae, but also for blocking out and preventing the spread of disease in our tanks. As the strains pass through the UV filter, they die off (theoretically). But some strains (such as ich) require different levels of exposure to the light in order to be killed. There is a certain range which is best (I am unsure of the exact number, and this likely does vary among tank sizes) and even then some can still pass through.

Some people (with reef tanks) see UV filters as a waste of money as they feel the UV light is not potent enough to the specific bacteria; others feel it is too potent and may actually kill off things we want to keep in the water column (but don't have appropriate equipment to test for).

I don't run a UV filter on my own tank, and many hobbyists don't, for reasons listed above. I prefer to keep a tank lightly stocked and keep the equipment / filtration simple. While we cannot fully prevent or irradiate it, lowering the number of fish (especially larger and/or aggressive ones) and allowing time between when you introduce new fish into your system should help in preventing marine-ich, and other stress-related diseases our fish may obtain.

 

Nice answer. If I was going to run one it would be grossly oversized, a small one is likely inconsequential. An oversized one is great for preventing cyano, diatom invasions etc.

 

UV can only kill what goes through it. Cyano lives on the surfaces of the aquarium, rocks, sand etc... So, UV has no effect whatsoever on it. The same is true for pretty much all nuisance algae in our aquariums. Only free floating algae, such as phytoplankton are effected, however, usually these aren't an issue and are more likely beneficial, if anything. Diatoms for example, are rarely an issue in an established aquarium and may serve as a food source for various pods. There just aren't really many free floating nuisance algaes other than the green algae that grows on your glass.