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Algae Control Info

How to Reduce Pond Algae Naturally - For Small and Large Ponds

In a nutshell: Pond algae needs two things to grow: sunlight and nutrients. You can block the sunlight from entering the pond water by using an aquatic sunblocker or pond dye like Aquashade. This will also help reduce pond weed growth as pond weeds also need sunlight in order to grow.

You can reduce the nutrients in the pond thereby starving the pond algae by using a beneficial bacteria for ponds.  The good types of bacteria eat up the excess nutrients including: sludge, muck, dead pond weeds, uneaten fish food, fish wastes, etc.  The best product to use for large ponds and lakes over 50' x 50' in size or thereabouts is PlanktoniX. It has trillions of good types of bacteria in each treatment that work at eating up excess wastes and nutrients and helps to keep your pond clean. For small ponds and water gardens, we recommend using Microbe-Lift.

How to Kill Pond Algae Mechanically

If you want to kill pond algae mechanically, you can use a ultraviolet clarifier or ultraviolet sterilizer. These are units that get plumbed into your filtration system and the pond water passes by a UV light and kills microscopic algae cells, viruses, bacteria, etc. A UV Sterilizer kills more than a UV Clarifier but a UV Clarifier is just fine to use for a koi pond or water garden. The intake water will typically come from a pump with a pre-filter on it to filter out larger debris.  Then, it will pass through the UV unit and the discharged water should go into a mechanical filter that will catch the dead algae cells before the water goes into the pond. It's really important that you set it up this way so the dead algae cells don't add more waste into the pond to feed more unwanted algae. 

How to Kill Pond Algae with an Algaecide

If you want to control your pond algae and kill it, you can also use a chemical designed for doing just that.  They're called an algaecide or algicide. It's important that you follow the instructions from the manufacturer.  Algae (and pond weeds, for that matter) rob oxygen out of the pond as it's dying. If you add too much algaecide at once, you can rob too much oxygen out of the pond and your fish may suffer and die. Typically, algaecides suggest treating around 1/3 of the pond at a time.  So, you will have to measure your pond and have a good idea of how much water it holds. An average estimate is to calculate the following: length of pond x depth of pond x width of pond x 7.5 = the amount of water it holds. This is just an estimate. When in doubt, under treat it so you don't have a fish loss. A few days after your last algaecide treatment, you can add your beneficial bacteria like PlanktoniX for large ponds or Microbe-Lift for small ponds.  This will help decompose the dead algae cells, sludge, muck, etc. We don't recommend the use of copper sulphate to do this. Copper sulphate creates a build-up of copper in the bottom of the pond and it creates havoc with the pond's health. It will also kill important microbes and bacteria that you're trying to harvest that's vital for a healthy ecosystem. People often tend to overtreat their pond with copper sulphate, too as each treatment application tends to become closer and closer together because the dying algae are providing nutrients to create more algae to grow. If you chose to use an algaecide, be sure to get one that's allowed in your state as some states restrict the use of certain algaecides.  This is where using a great beneficial bacteria product is even more important as they're not considered chemicals and are natural products.  So, get at the root of what's causing the algae to grow in the first place and you'll be further ahead.