Pond muck is the organic material that accumulates in the bottom of a pond. It can be physically removed with nets and vacuums, or you can try to degrade it using commercial bacterial products such as MuckOut, Macro-Zyme, Muck Pellets, MuckAway, Natural Clear, Mukk Busster, Muck Reducer, Muck Doctor, MuckBiotics and the product name I really like, ” Get The Muck Outta Here”. All of these products claim to reduce the amount of muck in the pond and some also claim to reduce the nutrient level.
Do commercial muck reducers work?
What Are Muck Reducing Products?
All these products contain bacteria. Bacteria play a major role in degrading organic matter in a compost pile, and they also naturally degrade the organic matter at the bottom of a pond.
The science is clear. Bacteria do degrade organic matter. But that does not mean adding some to a pond will speed up the degradation of muck in the pond. Claims like this, “MuckAway tablets sink below the water’s surface and dissolve, releasing hungry beneficial bacteria that instantly begin consuming and digesting the settled debris”, ignore the fact that the water and muck is already full of hungry bacteria.
Some of these products also include enzymes like lipase, protease, amylase, and cellulase. These are common enzymes produced by microbes to digest organic matter.
Scientific Evidence Provided By Manufacturers
I have looked at several of these products and none of the manufacturers provide scientific evidence that their product works.
I spoke with a product specialist at Airmaxeco, the manufacturer of MuckOut, Mukk Busster and Muck Away. He confirmed that they have not done any scientific studies on their product. He went on to say that “all of their evidence is anecdotal”.
I did find an independent study that looked at Mukk Busster, dated March 2022. They tested it on samples from three different lakes and found no change in organic matter even though the quantity of material they used was higher than recommended.
The same study also looked at bacteria populations. Each lake had a different type of bacteria dominating the water. Adding the muck reducer did not change the population. What this means is that the added bacteria did not become dominant. The product did not significantly change the bacterial population – it did not work!
This same report also referenced another non-peer reviewed study that looked at the addition of microbes along with aeration and found little to no effect (Slagle and Allen 2016).
Bacteria Decompose Pond Muck
What happens when bacteria decompose organic matter? Some of the carbon will be released as CO2, which will escape into the air. Some nitrogen and sulfur may also escape into the air as nitrous oxide, sulfur dioxide or hydrogen sulfide. All of the other nutrients will remain in the water since they are not turned into gases.
As bacteria consume the organic matter the population of bacteria grows. In effect the organic matter is converted into other organisms like bacteria and algae which are in turn consumed by larger organisms. Bacteria don’t live very long and when they die they become part of the organic muck at the bottom of the pond and the cycle continues.
There are two key points here. The amount of organic matter is slowly reduced because some of it is lost as CO2. At the same time the plant-available nutrient level in the pond will increase. Plants and algae are able to take these nutrients, along with CO2, and produce more plant matter.
This process happens all of the time, even when no commercial bacteria are added to the pond.
Do Pond Reducing Products Add Special Bacteria?
You might think that these commercial products consist of special bacteria that are not normally found in ponds, but that is not the case. What these products do is grow standard bacteria and provide them in a concentrated form.
A key question to ask is, do these products increase the bacterial population in the pond? The claim is that they do, but these companies provide no evidence that this actually happens. In fact the expert from MuckOut told me that they have never measured the bacterial population in a pond before and after adding their product. They don’t know if the population increases.
You might be thinking that this is obvious. If you add bacteria to a pond, the number must go up, but that is not true.
Bacteria multiply very quickly. Add a little food to a pond and the number of bacteria explodes to make use of the new food source. The population is very dynamic and changes quickly with a change in the environment (food, oxygen, temperature, etc). However, the population is always at capacity (i.e. maximum potential). Adding more bacteria to the pond does not increase the population because it is already at maximum capacity, given the current environmental conditions.
The exact same thig happens in soil. For details see, Buying Soil Probiotics (Microbes) – Are They Beneficial, Effective or Nonsense?
One of the manufacturers makes a point of saying, “bacteria counts double every 15 minutes or so”, and that is true provided there is a ready supply of food. If the food was in the pond for this to happen the natural bacteria in the pond would have already exploded in growth and you would not need to add more.
Note that the above mentioned study found no change in the bacterial population after Mukk Busster was added.
Is Muck Food For Bacteria?
Organic matter is food for bacteria, so why do the natural bacteria not clear out the muck more quickly?
This is the same process that takes place in a compost pile. You have probably heard of the fact that you need the right ratio of browns to greens in order for fast decomposition. It is actually not browns and greens – that is another myth you can read about here. It is about the carbon to nitrogen ratio (C/N ratio). If the C/N ratio is between 20 and 30, bacteria have a perfect food source and decomposition happens quickly.
Unfortunately, the organic matter at the bottom of the pond is mostly carbon – old leaves and dead plant material – and the C/N ratio is much higher than 30. It does not compost quickly because there is too much carbon relative to nitrogen. This also explains why a pile of leaves on the ground decomposes so slowly – a very high C/N ratio.
The C/N ratio does not change when you add extra bacteria into the water. Bottom line – muck is a poor food source for bacteria and that is why it accumulates.
Do Enzymes Remove Muck?
The enzymes that are added by some products will help break up organic matter. However, is the quantity added significant enough to make a difference?
Keep in mind that enzymes are also organic molecules and are subject to degradation. None of the manufacturers make any specific claim for them, except that they “do work”.
Do Muck Reducers Remove Muck?
I don’t see why they would work and unfortunately, the manufacturers have not done studies to show they work. That should tell you something.
Manufacturers suggest that these products work better when they are applied regularly and that adding bubble aeration helps a lot. The air circulation will help move muck from the bottom to upper levels of water and the extra oxygen will speed up decomposition. But aeration will do this on its own without added bacteria.
I suspect the added bacteria have a limited effect on muck. Show me some studies that say I am wrong.
Do Muck Reducers Remove Nutrients?
Even if the products speed up the decomposition of muck they can’t remove the non volatile nutrients which includes everything except nitrogen and sulfur. The nutrients stay in the pond and are available for plant use. Unless you have a lot of higher order plants, the excess nutrients will cause algae to grow.
MuckAway claims to reduce phosphorus levels in the pond by 90% but they do not provide a scientific study that shows this. Phosphorus is not volatile. The only way to remove it from a pond is to physically remove it, which makes this claim unbelievable.
Some product descriptions claim to remove nutrients along with the muck, but these are wrong. The expert at MuckOut/MuckAway even confirmed this with me. The nutrients stay in the pond.
Do Muck Reducers Work?
Given the number of products on the market and the fact that they have been around for some time, it is surprising that there is so little research on them. I suspect the scientific community has reservations about their effectiveness given what we know about the biology of bacteria. The manufacturers seem uninterested in funding research to prove their products work, which is not a good sign.
Muck reducers will not remove nutrients from ponds except possibly for nitrogen and sulfur. Therefore they have limited effect on algae growth.
Given the rapid rate at which bacteria multiply, the large amount of natural bacteria in ponds, the relatively small amount that is added by these products and the C/N ratio of the muck, it is unlikely that these products reduce pond muck.
Until manufacturers provide some independent scientific data to prove these products work, I would not buy them.