UltraClear Cold Water Muck & Sludge Remover
- Active in cold pond water from 32°F to 55°F
- Sinking pellets help break down leaves, fish waste and sludge
- Helps reduce organic buildup and odors before spring
- Safe for koi, fish, plants and wildlife when used as directed
- Made in the USA; formerly UltraClear Autumn Prep
Description
Less winter buildup. An easier spring opening.
Fallen leaves and fish waste settle on the pond bottom just as the weather turns cold. UltraClear Cold Water Muck & Sludge Remover uses sinking beneficial bacteria pellets to help break down that organic debris in water from 32°F to 55°F.
Formerly UltraClear Autumn Prep. Same cold-water formula, clearer name.
Works where the muck collects
- Targets bottom debris: sinking pellets reach the leaves, fish waste and sludge that collect on the pond floor.
- Supports cold-season pond care: use during fall, unfrozen winter periods and early spring to help reduce organic buildup and odors.
- Simple to apply: measure the label dose and scatter evenly. No premixing or special equipment.
- Safe for pond life when used as directed: a biological formula for ponds with koi, fish, aquatic plants and visiting wildlife.
- Made in the USA: backed by UltraClear pond care experience since 1993.

Your cold-season routine
- Check the water temperature. Begin as pond water cools below 55°F.
- Measure and scatter. Follow the package dosing chart for your pond size, then distribute the pellets evenly across the water surface.
- Repeat as directed. Ponds up to 1,000 gallons are dosed weekly; larger ponds are dosed monthly. Follow your package label for the amount.
- Resume after thaw. The bacteria become dormant during freezing conditions and resume activity when the water thaws into the working temperature range.
- Switch for warmer water. Above 55°F, use UltraClear Muck Digester Tabs for warm-season bottom maintenance.
Choose your size
Available in 0.75 lb, 3 lb, 5 lb and 10 lb. Choose for your pond size and the number of applications you need. Check the dosing chart on your selected package; container size alone does not determine how long treatment will last.
Need help measuring your pond? Use the UltraClear Pond Calculator or contact us for dosing help.
Common questions
Does it work if my pond freezes?
The bacteria pause during freezing conditions and resume when the water thaws. Use within the 32°F–55°F working range and follow the label directions.
Is this the same as Autumn Prep?
Yes. UltraClear Autumn Prep is now Cold Water Muck & Sludge Remover. The cold-water formula is the same.
When should I switch to Muck Digester Tabs?
Switch when pond water rises above 55°F. Cold Water Muck & Sludge Remover is designed for the cooler part of the year.
Less winter buildup. An easier spring opening.
Fallen leaves and fish waste settle on the pond bottom just as the weather turns cold. UltraClear Cold Water Muck & Sludge Remover uses sinking beneficial bacteria pellets to help break down that organic debris in water from 32°F to 55°F.
Formerly UltraClear Autumn Prep. Same cold-water formula, clearer name.
Works where the muck collects
- Targets bottom debris: sinking pellets reach the leaves, fish waste and sludge that collect on the pond floor.
- Supports cold-season pond care: use during fall, unfrozen winter periods and early spring to help reduce organic buildup and odors.
- Simple to apply: measure the label dose and scatter evenly. No premixing or special equipment.
- Safe for pond life when used as directed: a biological formula for ponds with koi, fish, aquatic plants and visiting wildlife.
- Made in the USA: backed by UltraClear pond care experience since 1993.

Your cold-season routine
- Check the water temperature. Begin as pond water cools below 55°F.
- Measure and scatter. Follow the package dosing chart for your pond size, then distribute the pellets evenly across the water surface.
- Repeat as directed. Ponds up to 1,000 gallons are dosed weekly; larger ponds are dosed monthly. Follow your package label for the amount.
- Resume after thaw. The bacteria become dormant during freezing conditions and resume activity when the water thaws into the working temperature range.
- Switch for warmer water. Above 55°F, use UltraClear Muck Digester Tabs for warm-season bottom maintenance.
Choose your size
Available in 0.75 lb, 3 lb, 5 lb and 10 lb. Choose for your pond size and the number of applications you need. Check the dosing chart on your selected package; container size alone does not determine how long treatment will last.
Need help measuring your pond? Use the UltraClear Pond Calculator or contact us for dosing help.
Common questions
Does it work if my pond freezes?
The bacteria pause during freezing conditions and resume when the water thaws. Use within the 32°F–55°F working range and follow the label directions.
Is this the same as Autumn Prep?
Yes. UltraClear Autumn Prep is now Cold Water Muck & Sludge Remover. The cold-water formula is the same.
When should I switch to Muck Digester Tabs?
Switch when pond water rises above 55°F. Cold Water Muck & Sludge Remover is designed for the cooler part of the year.