The cookie settings on this website are set to 'allow all cookies' to give you the very best experience. Please click 'Ok' to hide this message.

Algae Prevention

21st Nov 2019

Algae is not a problem that you can set your clock by, it may be a problem one year and not the next. It is easy to see why people can get frustrated having to frequently use treatments, as it can get expensive. In realistic terms problems occur when we have sunshine (No sign of too much of that this year so far, unfortunately!) …So it can be difficult to predict when or if algae will become a problem. As the old adage says, ‘Prevention is always better than the cure.’

Treatments are obviously only a short-term solution and therefore should not be relied upon. The best way to keep on top of algae is by doing a bit of forward thinking beforehand to prevent it becoming an issue in the first place.


Correct pond management is by far the best way to start. Reducing the amount of sunlight your pond receives is the first step, pergolas are popular these days and personally, I think they look great! If you can incorporate this kind of shade into your build, then you’re one of the lucky ones. If not simply using some shade netting may be the way to go, every little helps! One thing to note when you’re thinking about building your pond, is don’t rely on trees for shade. Falling autumnal leaves are a nightmare for pond keepers as they can seriously affect your water quality as they sink to the bottom of the pond and rot - and they can be a real chore to suck up with a pond vacuum.


nother common cause of algae that many people fall foul of is overstocking and overfeeding. To prevent the growth of algae, don’t do either! Most of us get into the pond hobby for the fish, we like loads of them and sure enough everyone who comes around to the house wants to feed them! This bumps up the nutrients going into the pond tenfold, an effective filtration system is therefore needed to ensure top water quality, however these will not remove the nitrates and phosphates that feed the algae within our pond.

The pond pellets, flake or sticks that we feed our fish can have a huge impact on the amount of algae within our ponds. Most fish food these days is of pretty good quality, we know ours is anyway! Dust in fish food should be pretty much non-existent, so if you purchase a fish food with noticeable dust in amongst the food I’d say to avoid this, as it will just aid the growth of algae. Get yourself over to our Food Section and pick up some good quality stuff!

Removing Nitrates and Phosphates

As mentioned earlier removing nitrates and phosphates isn’t done by a ‘normal’ filtration system. There are two types of filtration systems that will achieve this though, a protein skimmer is one of them as it will help to reduce the overall load of protein within your pond. Algae can’t directly use protein alone, however removing it from your pond helps, you will also never get dreaded foam on the surface of your pond!

More importantly though is the use of plants, when suggesting incorporating plants into the pond I often hear ‘I can’t have plants because my Koi eat them’ – this might be a common thought, however there are still ways of incorporating plants into any pond, and personally I think they are vital. An old-fashioned vegetable filter is a tool that many have forgotten in their pond planning, and it is actually kind of frowned upon within the Koi world. Ponds here tend to be straight edged to allow full appreciation of the fish themselves, but if you can I would strongly advise adding at least a marginal area within the pond plan itself. If you can’t do this maybe have a look at my blog on floating planters - mine have never been knocked over by my koi and they look great!