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Sludge is a common problem for pond owners and unfortunately, it’s inevitable. Although it’s not too much of a problem when found in traces and small quantities.

However, when your pond contains a build-up of sludge, we’re talking the thick, gunky stuff that sits as a layer at the bottom of the pond and always certainly has an odour, that’s where the problems begin to kick in.

With this being such a common problem for many pond keepers, it only makes sense to provide a better understanding of what pond sludge actually is, how it occurs, the potential issues of leaving it untreated and what pond keepers can do to keep it under control.

What Is Pond Sludge?

Pond sludge is made up of the organic materials that are found in and around your pond.

Ranging from fish food, faeces and plant debris, it is the end product of when all of this matter falls to the bottom of your pond and begins to rot.

At first, this process may be barely noticeable when you have little to no debris in your pond, however as time goes on and more matter breaks down, the sludge becomes thicker and therefore impenetrable to oxygen. The sludge eventually takes up an anaerobic state that causes the bacteria within the pond to produce Hydrogen Sulphide. As many of you will know, Hydrogen Sulphide smells like rotten eggs (you may have come across this smell after disturbing the bottom of your pond or cleaning out your filters).

Hydrogen Sulphide is toxic. Due to its nature of interfering with the oxygenation and respiration of aquatic life in ponds. This begins with how Hydrogen Sulphide kills off aerobic bacteria which are typically responsible for breaking down organic matter and algae.

Pond sludge, in essence, contributes to the occurrence of algae blooms as there aren’t sufficient amounts of beneficial aerobic bacteria in the pond to break down and keep up with the rate of algae growth. The lack of bacteria will then lead to your pond plants and fish suffering, deteriorating and eventually dying. As more and more of your pond life dies it adds to your layer of pond sludge and creates a vicious cycle.

However, pond sludge is not the end of the world and if you have sludge in your pond, don’t worry, it is easy to treat and we will come back to this.

How Do I Prevent Pond Sludge?

Preventing and minimising the amount of sludge is easy enough to do and will keep your pond running efficiently. Be sure to remove any floating debris as and when you see it. Take care when cutting your lawn as lawn cuttings can easily find their way into the pond and quickly sink to the bottom.

Finally, use aquatic cloth liners or aquatic gravel in submerged plants to keep the fish from digging them up. Koi especially, find digging up plants very amusing!

In autumn, sludge can become the biggest problem in the pond. Check out the following blog to find out how to prevent it:

5th October

Prevent Pond Sludge Build Up in Autumn

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How to Remove Pond Sludge?

So, you have done all you can to prevent this layer of sludge from forming, but the inevitable has happened and you have acquired pond sludge.

There are two things you can do at this point. You can either physically remove the pond sludge using your hands or a pond vacuum. These will get rid of the physical matter but will remove some of the helpful, aerobic bacteria and leave behind some of the harmful Hydrogen Sulphide.

The second thing you can do is to add extra, beneficial bacteria into the pond to “attack” the pond sludge, break it down and digest it whilst topping up the aerobic bacteria in your pond. Envii Sludge Klear contains a unique blend of bacteria and enzymes that break down and digest the pond sludge. Sludge Klear can be used as a treatment product and maintenance product to keep your bacteria levels high and sludge levels low all year round.

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