Water drains onto fleece
Overflow water lands on a sheet of fleece stretched across a roller, and the fleece traps fine particles.
Filtration & equipment
Fleece rollers
A fleece roller is an automatic mechanical filter for a sump. Water passes through a sheet of filter fleece, and when the fleece clogs, a motor rolls fresh fleece into place and winds the dirty section out of the way. You will mostly see them on saltwater and reef sumps.
What it does
How a fleece roller works
It sits where the overflow drains into the sump and catches particles before the water reaches the rest of the system.
The fleece slowly clogs
As debris builds up, water passes through more slowly and the level behind the fleece rises.
A float switch triggers
A float or level sensor notices the rise and tells the motor to advance the fleece.
Clean fleece rolls in
Fresh fleece comes off the supply spool while the dirty section winds onto the take-up spool, out of the main flow.
Compare
Fleece roller vs socks and sponges
All three catch debris. The difference is how often you have to touch them and how long the waste sits in the water.
Simple, but hands-on
Socks catch debris well but need swapping every few days. A full sock overflows or bypasses, and trapped waste keeps breaking down in the water.
Reusable, but need rinsing
Sponges hold a lot of debris and can be rinsed, but they still need regular cleaning and collect waste between services.
Filter media guideAutomatic and consistent
Fresh fleece stays in the flow and dirty fleece is wound out of the way on its own. You mainly change rolls and check the parts.
Pros and cons
Is a fleece roller right for you?
Rollers save a lot of routine work, but they take space and still need care.
Why people use them
- Less hands-on mechanical filtration
- Waste leaves the flow before it breaks down
- Steady, predictable performance
- No dirty socks to wash
What to weigh
- Costs more up front than socks
- Needs sump space and room above the water
- Ongoing fleece rolls and a motor that can fail
- Used fleece goes in the trash
It catches food too
Fleece traps fine particles, including coral food. Many keepers pause the return pump while feeding so food stays in the display longer.
Export, not a cure-all
A roller removes solid waste before it rots into nitrate and phosphate. It does not remove dissolved waste, so a skimmer, water changes, and testing still matter.
How to choose
Size it to your sump and flow
Measure before you shop. Check the manufacturer's dimensions and flow rating against your own numbers.
Measure the chamber
Note the filter section's width, length, and height, the water level there, and room above for the motor, spools, and your hands.
Rate it above your real flow
Pick a roller rated above what your return pump actually delivers after head loss, so it is not advancing constantly.
Pumps and flowPlan the plumbing
Overflow drains need to land in the roller inlet. Note how many drains you have and their size.
Plumbing partsAll-in-one and nano tanks
Compact rollers are made for some all-in-one tanks and small sumps. Confirm the model fits your rear chamber.
Possible, less common
Rollers work on freshwater sumps too, but most freshwater tanks use canister or hang-on-back filters.
Maintenance
Keep it rolling
Automatic does not mean maintenance-free. A quick look most days catches problems early.
Check the roll
See that the fleece advances normally and how much is left.
- Watch for a sudden jump in use
- Make sure water goes through the fleece
- Keep a spare roll on hand
Keep the sensor clean
A stuck float can make the roller run nonstop, or never advance so water bypasses the fleece.
- Wipe off salt creep and slime
- Check for snails or debris
- Confirm it moves freely
Replace the roll
When the roll runs out, unplug the unit, remove the full take-up spool, and thread a new roll the same way.
- Use fleece sized for your unit
- Thread it flat, with no wrinkles or gaps
- Used fleece is usually thrown away
Rollers and motor
Look over the gears, rollers, and motor housing during regular maintenance.
- Clear salt creep from moving parts
- Keep any bypass or emergency overflow clear
- Listen for grinding or slipping
Common mistakes
What usually goes wrong
Most roller problems trace back to sizing, a dirty sensor, or expecting it to do every job.
Blaming the roller for fast fleece use
A roll that runs out fast usually reflects feeding and stocking. Treat fleece use as a clue.
Feeding basicsNot testing after install
Nitrate and phosphate can drop faster than expected. Test weekly for the first few weeks and adjust slowly.
Track parametersDropping other filtration
A roller is mechanical filtration only. Keep your skimmer, biological filtration, and water changes.
Protein skimmers