How do I control Algae in my Aquarium and/or Pond?

We have all been there. We have all looked into our tank or our pond to see the familiar green/brown/black growth that is algae. Sometimes it springs upon us by surprise. Other times it is the slow encroachment which we just cannot seem to contain. This can be incredibly frustrating because all the effort you put into making the tank/pond look good is now wasted. The beautiful ornaments, the aquatic plants, all have this layer of slimy, green film over the top.

Why does algae grow more at certain times that others? How do you get rid of algae? How to you maintain the algae-free look?

Algae Growth

One reason for algae growth might be high levels of phosphate, nitrate, or iron in your tap water. You can test for some of these at home. In these conditions algae can flourish.  If it’s not in your treated city-water, then it could be from the decomposition of excess fish food. Making sure that you feed the correct amount to your fish has benefits on a number of levels!

Too much light can also cause algae to bloom. This could especially be sunlight. If you pond or tank is not shaded for much of the day, this could be the reason for the algae growth. Consider a shade sail for your pond (which will also benefit any fish in there) or repositioning your fish tank in a shadier corner of the room. Alternatively, keep the nearby window covered until the sun direct rays have passed. Even too much artificial light might promote algae growth. If this is your trouble, consider turning the light on later in the morning, or off earlier in the evening.

Some types of Algae:

  • Blackbeard Algae
  • Blue-green algae
  • Brown algae
  • Blanket weed
  • Fuzz algae

Most types of algae are caused by some imbalance in your water: CO2, nitrates, low oxygen, high phosphates, high silicates, low nutrients. This is why algae might happen frequently in new tank setups which are “immature” in terms of the beneficial bacteria and their cycles.

Getting Rid of Algae

Firstly, getting rid of algae requires cleaning - algae pads or magnetic cleaner. It requires removal of as much of the algae as you can. This means off the glass, and off the ornaments. If your algal growth is only small, this can sometimes contain the growth. Simply clean the glass and maybe an ornament or two each day when you go to feed your fish. However, this can often be insufficient for larger algal blooms.

You might need to use an algaecide like API Algaefix (aquarium and pond versions available), or Pets Pond Algae Killer. This specifically targets the algae and is safe for the rest of your fish. If you have other types of aquatic animals in your tank/pond, then be sure to check the label.

Splosht is a great non-chemical alternative to algaecide with the same results! Splosht is a blend of good bacteria that consumes excess nitrates, phosphates, ammonia, and ‘sludge’ – which we said is the reason for most algae growth. This product takes 4 weeks to work (for the bacteria to grow), but after that you can use doses to maintain water clarity.

Certain species of fish are algae-eaters too! Siamese flying foxes and Bristlenose catfish are ideal for tropical tanks, and Sucking catfish for cold water tanks and ponds.

Maintaining Algae Free

After all the effort you put into a large clean and the money for the algae-fixer, you want to maintain a low algae environment. Small doses of your algaecide or Splosht will maintain your algae-free environment. Pond One Algae blocks can be used since they are a slow release algaecide and can be dropped into the water quite easily. One small square can do up to 200L!

A number of pond pumps/filters also come with a UV steriliser to kill algae.

With this new knowledge and the correct products, you can have the crystal clear water you desire!

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