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​Algae Control and UV Clarifiers

Will an UV clarifier take care of all the algae growth?
 
A major cause for algae is excess fish waste and dead organics from leaves or previous algae blooms combined with sunlight, leaving your pond with green living intrusions Is a UV clarifier the answer? It depends on the type of algae. The algae that forms in your pond comes in two basic types planktonic and filamentous. 
​
  • Planktonic algae, the source of pea soup algae blooms, are floating, microscopic plants that color pond water shades of green, blue-green, brown or variations . • In controlled amounts, this type of algae can actually be beneficial. It's considered the start of the pond food chain as the tiny plants feed fish inhabitants, and it can also shade the pond's bottom, preventing subsurface nuisance plants from growing. In uncontrolled amounts, however, planktonic algae can cause oxygen depletions and fish kill. 
  • Filamentous (string) algae are single-celled plants that form long, visible chain, threads or filaments. These threads, which start growing along the bottom of the pond in shallow water or on rocks or other aquatic plants, intertwine and form mats that resemble wet wool. When these mats rise to the surface, they're commonly referred to as pond scum. These mats make great homes for micro- and macro-invertebrates, like bugs and worms, but they're also unsightly. UV clarifiers work by destroying the ultrafine planktonic algae – but, unfortunately, they do nothing to combat the filamentous algae.
Battling Planktonic Algae
So how does ultraviolet light fight planktonic algae? When the algae cells are exposed to the bulb’s ultraviolet rays, radiation destroys the plants’ cellular walls. As a result, the tiny particles of dead algae clump together, and those clumps are then removed by your mechanical filtration system.

For proper UV help:
  • Replace bulbs yearly. Worn-out bulbs – even if they still light up – may not be as effective at controlling green water. 
  • Watch your flow rate. Pushing water past the UV too fast can damage the unit and not allow enough contact time with the UV bulb for it to be effective. 
  • Don't flow too slow. Running a UV at too slow of a flow will act as a sterilizer and may also have a negative effect on natural bacteria meant to help decompose dead organics and fish waste.

Finding Balance

If you have an algae problem, be it planktonic or filamentous, it indicates your pond is out of balance. An ultraviolet clarifier should actually be one of your last tactics! Add some beneficial bacteria to help reduce the amount of organics in your pond. Start aerating the water. Consider using pond dye which will give artificial sun shade. Manage the nutrients, sunlight and oxygen levels, and your algae proliferation should naturally level out on its own.

Inspired by an article in The Pond Guy Blog. Reproduced with kind permission.

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