UltraClear Muck Digester – 32oz – 47125


Treats 32000 Gallons

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Eliminate pond sludge and pond muck. Eliminate sediment from fish & animal waste, decayed leaves and grass, and eliminate organic decay from dead fish & wildlife. Prevent oxygen depletion from unhealthy pond sludge during the spring & summer.

Pond Sludge accumulation occurs for a variety of reasons. Leaves and grass clippings can be blown into the pond. Droppings from animals such as fish, ducks, or geese can sometimes be significant. Even over-feeding the fish in the pond can promote sludge accumulation. In many ponds, the largest contributor to pond sludge (or muck build-up) build up is dead algae. Every year, algae populations increase to at least some extent during the warm sunny months. These algae die off, and then become part of the pond sludge accumulation.

Pond sludge build-up causes four significant problems. First, it results in an anaerobic zone (meaning a zone without significant dissolved oxygen). An anaerobic zone is a place where potentially dangerous, disease-causing bacteria (pathogens) tend to grow. The larger the anaerobic zone (meaning the greater the depth of sludge build up), the greater the potential for significant populations of pathogenic bacteria in the pond, which can harm fish.

Second, pond sludge build-up is the main cause of unpleasant pond odors. When the build-up is significant, hydrogen sulfide (which has a rotten egg odor) is produced. And hydrogen sulfide is not only odorous, but can poison fish.

Third, pond sludge build-up may deplete oxygen reserves, particularly during warm weather. The worse the build-up of pond sludge or muck, the worse the oxygen depletion. Low oxygen levels can be stressful or even fatal to fish or other wildlife.

Fourth, as pond sludge (or muck) build-up reaches excessive levels, nitrogen and phosphorous that is part of the sludge will slowly be released. This nutrient release can cause severe water quality problems, including algae blooms.

Of course, the larger and deeper the pond, the more difficult it is to mechanically remove the pond sludge build-up. But there is a simple way to control sludge build up. Dose the pond as described below with UltraClear Sludge Digester. Routine dosing maximizes your results for reducing muck that accumulates as pond sludge.

How Does Ultra Clear Sludge Digester Work

UltraClear Sludge Digester contains a variety of bacteria that digest sludge. It includes a class of bacteria that is facultative that works in an aerobic or anaerobic zone. First, it must be emphasized that Sludge Digester (or any biological product) is capable of digesting organic sludge, but not inorganic material such as sand, silt, or clay. Organic sludge refers to sludge of biological origin, such as leaves, grass, animal droppings, and dead algae.

Some natural bacteria have the ability to vigorously attack the basic building blocks of organic sludge, such as proteins, starches, fats, and cellulose. In fact, UltraClear Sludge Digester is super-enriched with these types of bacteria.

Sludge Digester is used in two main ways.

1. Season-long application designed to prevent excess sludge build-up

2. Fall Clean-Up to thoroughly clean the pond and provide a fresh start for the next pond season. Preventing muck build-up year round helps keep a healthier pond. UltraClear Sludge Digester is effective in cold water down to 40 degrees F.


It is very important to understand the difference between each application type, and to use the product as directed.

Dosage for General Pond Maintenance (minimizing sludge build-up)

You can begin maintenance treatment at any time. But for the most protection, begin treatment in the spring, and continue through the beginning of fall. If you reside in a year-round warm region, dose all year long.

Dose the pond with one ounce of Sludge Digester for every 1000 gallons of water (note: 1000 gallons = 135 cubic feet). Repeat this dose at least once a month, and as often as once a week. But do not dose sludge digester more often than once a week during the pond season.

For best results, dilute the recommended Sludge Digester dose into a gallon of pond water. Briefly mix, then dose the gallon of product diluted in water around the pond. If there are known areas of sludge accumulation, or areas where there are known odor problems, concentrate more of the dose there.

Why is it important not to dose more frequently than once per week? The answer is that while the maintenance dose is completely safe and appropriate for any pond, heavier doses during the pond season may actually cause problems. Warm water holds less oxygen than cooler water. During peak summer temperatures, oxygen levels are lower than during the fall. Normal maintenance use will digest sludge slowly but steadily. Any time there is sludge digestion, some pond oxygen will be consumed or depleted. If you overdose the product, or significantly exceed the maintenance dose, you may significantly deplete oxygen in the pond.

Also, when sludge is digested too fast, nitrogen and phosphorous are released. These nutrients may cause algae blooms, particularly during intense sunlight.

The Sludge Digester maintenance dose prevents excessive sludge build-up, but will not deplete oxygen levels or release excess nutrients. Be sure to follow maintenance dose guidelines (one ounce for every 1000 gallons, at least once a month, but NOT more than once a week).

Dosage for Fall Clean-Up

When the pond season is over and fall is at hand, temperatures and sunlight intensity are reduced. At this time, much heavier Sludge Digester application will clean your pond and give you a fresh start for the next season – without causing oxygen depletion or an algae bloom. Cooler water holds oxygen much better than warmer water. And of course, algae blooms are much less a problem in the fall than during the peak of the summer.

Dose the pond with one ounce for every 1000 gallons of water, daily, for 4 to 7 consecutive days.

For best results, dilute the recommended Sludge Digester dose into a gallon of pond water. Briefly mix, then dose the gallon of product diluted in water around the pond. If there are known areas of sludge accumulation, or areas where there are known odor problems, concentrate more of the dose there.

Why is UltraClear Sludge Digester Better than Competing Products?

Sludge Digester is strong enough to prevent excess build-up, but gentle enough to avoid oxygen depletion or nutrient release during the sensitive, peak summer season. Then, when fall arrives (with reduced temperatures and sunlight intensity), Sludge Digester is used aggressively to thoroughly clean the pond without fear of oxygen depletion or nutrient release.

Many pond owners use both our Biological Pond Clarifier and Sludge Digester at the same time. When using both products as directed, optimum results are achieved. Your pond remains crystal clear, and bottom sludge is kept to a minimum. And of course, one product or the other can be used individually, based on your specific pond conditions.

Most competing products are formulated for both pond clarification and sludge digestion at the same time. Unfortunately, these are often competing purposes that are not well-served with a single formulation.

For example, during the peak of summer, it might be desirable to add more product in hopes of improving pond clarity. But this may cause problems if the product is also designed for sludge digestion. UltraClear offers separate products to prevent this problem (Biological Pond Clarifier for pond clarity and beauty, plus Sludge Digester for minimizing build-up and fall clean-up).

How Safe is UltraClear Sludge Digester?

The bacteria included in UltraClear Sludge Digester are recognized by the Centers for Disease Control and Prevention (CDC) and the American Type Culture Collection (ATCC) as Biosafety Level 1 bacteria. CDC and ATCC give the following definition of Biosafety Level 1 bacteria:

‘ATCC cultures and related products are classified by biosafety level (BSL) in an effort to provide guidance to the user on potential risk. The classification is based on assessment of the potential risk using U.S. Public Health Service guidelines, with assistance provided by ATCC scientific advisory committees. Those items in BSL-1 have no known potential to cause disease in humans or animals.’

As long as the product is used as directed (Maintenance dose throughout the pond season, and Clean-Up dose in late fall), Sludge Digester is a safe tool to help ensure a healthy, balanced aquatic environment.

Additional information


Pond Product Type

Pond Water Treatments

Bottle / Container Size

Pond Water Treatment Type


Muck Digester