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I’m tired of fighting algae. Will a UV take care of all the algae growth? | Decorative Ponds & Water Gardens Q & A

Q: I’m tired of fighting algae. Will a UV take care of all the algae growth?

Q: I’m tired of fighting algae. Will a UV take care of all the algae growth?

Cherice – Everett, GA

A: Who isn’t tired of battling algae!

Caused by excess fish waste and dead organics from leaves or previous algae blooms combined with excessive sunlight, all that garish green growth looks horrible, ruins your water quality, and creates a headache for you and your fish.

Is an ultraviolet clarifier the answer? It depends on the type of algae you’re trying to destroy.

Know Your Algae

The algae that forms in your pond comes in two basic flavors: 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 between. 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. You’ll need a different strategy for the stringy stuff.

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 the UV clarifier to work properly, however, follow these guidelines:

  • 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 affect 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 from the Pond Logic® DefensePAC® Pond Care Package to help reduce the amount of organics in your pond. Start aerating the water. Consider using pond dye. If you have a thriving fish population, think about finding a new home for them (but don’t release them into the wild!). Manage the nutrients, sunlight and oxygen levels, and your algae proliferation should naturally level out on its own.

Pond Talk: How dependent are you on your ultraviolet clarifier?

Quickly Clear Discolored Water - The Pond Guy® PowerUV™

My Koi & Goldfish Were Gasping for Air After I Treated for Algae. What Went Wrong? – Water Garden Q & A

Picture of String Algae of a Water Garden.

Q: My water garden looked like pea soup so I treated it with AlgaeFix. The product worked great although it took its toll on my fish. My koi and goldfish began gasping at the surface. I immediately did a water change and only lost one small goldfish. I have used AlgaeFix for years and never had this problem. What went wrong? – Lisa of Georgia

A: Oxygen. Oxygen. Oxygen. You must be careful when treating for algae, especially pea green water or planktonic algae. AlgaeFix® along with most algaecides on the market work very quickly. When the algae die, they begin to decompose immediately, robbing oxygen from your fish.

How to reduce your chance of fish loss:

#1 – Proper Aeration:Make sure you have an abundance of aeration before you treat for algae. Waterfalls, spitters and fountains all provide aeration. Although, the best source of aeration is generally an aeration system.

#2 – If treating for string algae, remove as much by hand as possible before any treatments. In the case of Lisa’s pea green water, I would have recommend that she do a 10-20% water change approximately 24 hours before her application.

#3 – Get to the root of your problems: Generally ,excessive algae blooms are caused by one or more realistically, a combination of the following: poor filtration, TOO MANY FISH or not enough aquatic plants.

#4 – Use natural products to provide clear water: Although chemicals, when used properly, are a helpful tool they should not be your only solution. For a healthy eco-system and more consistent clear water, turn to a natural remedy such as the DefensePAC® and/ or Barley Straw Extract.