Di-4 Drop-In Fleece Filter System

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Discontinued by Bulk Reef Supply
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Months of Maintenance-Free Filtration!

Klir Di-4 Filter Drop-In Fleece Filter System fits in most sumps with a 4" filter sock tray and will eliminate the need to replace filter socks. The 50-micron fleece roll will help eliminate free-floating particles and automatically advance when the fleece starts to clog, exposing new fleece. The Di-4 has the capability of handling up to 750 GPH and producing crystal clear water. 


Maximum Flow Rate - 750 GPH

  • Fits in tight areas
  • Compatible with most 4" filter sock holes
  • Includes 25 yards of 50-micron fleece
  • Fully automatic with smart controller
  • Removable lid with carbon insert for noise and odor control
  • Multiple units can be placed side-by-side


Traditionally filter socks have been used to polish aquarium water from particulates and detritus, and now with the Klir Di-4 Drop-In Fleece Filter System, you can throw away your filter socks for good! The Klir Di-4 can hold up to 25 yards of 50-micron fleece allowing it to last for months at a time without having to be maintained in any way. The compact design lets it fit in tight spaces, and since you only need to access it once every few weeks or months, having direct access like filter socks in no longer a concern. Some tanks may need to replace the fleece once every couple months where others may need to replace it more often, and that will depend on your bio-load along with feeding habits and a few other variables, but in most cases, a single fleece roll can last up to 3 months without having to be replaced. 

Klir Di-4 Dimensions


How the DI-4 Works

Water will be able to enter the Klir Di-4 from two sides and then travel down to the bottom where it can be pushed through the fleece material, where any particles will be collected. Over time the debris collected will start to clog the fleece tower and the water level will start to rise in the sock tray, and that is where the optical eye sensor comes into play. Once the water level reaches the eye, the Klir will automatically activate the roller, exposing new fleece and allowing water to flow freely again, dropping the water level below the sensor. 



Dimensions - 4.125" L x 4.125" W x 17.125" H

Flow Rate - 750 GPH max

Filter Sock Hole Requirements - 3.8" (min O.D.) to 4.25" (Max O.D.)

Power Consumption - 0.6A @ 12VDC



What's Included?

1x Klir Di-4 Filter Tower Assembly

25 Yards 50-Micron Fleece Roll

1x Motor Assembly

1x Controller Assembly

1x Optical Eye Sensor

1x Controller Power Supply

1x Activated Carbon Insert

1x 3.85" Filter Sock Adapter Plate

1x 4" Filter Sock Adapter Plate (preinstalled)

1x 4.25" Filter Sock Adapter Plate


Sump Requirements:

  • Sump with filter sock tray
  • Capable of holding 1.5" of water above the sock tray
  • 8.125" of space below the sock tray
  • 4.125" opening above the sock tray
More Information
UPC 6920042880108
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Product Questions

will this fit a aio with the 4 inch filter socks.. JBJ 45 all in one
Question by: Barrett Ellis on Nov 25, 2022, 8:26 AM
Thanks for reaching out! This should fit!
Answer by: James Johnson (BRS Staff) on Nov 26, 2022, 12:28 PM
Would this work in a water box 20? Or with a square filter sock holder?
Question by: Chris on Feb 19, 2022, 8:14 PM
Unfortunately, this is only compatible with either a 4" round filter sock holder or the Klir Di-4 Filter Bracket.
Answer by: Ashley Hoglund (BRS Staff) on Mar 3, 2022, 4:28 PM
Will this fit in the Trigger Systems Sapphire 20C Sump?
Question by: Adam on Jan 4, 2020, 10:18 PM
Hey there!

I am afraid it will not, the opening for the filter sock is too small.

Take care
Answer by: Thomas Billington on Jan 5, 2020, 10:35 AM
Does this fit in the skimz sumps?
Question by: Xiaoxi Yang on Aug 31, 2018, 9:19 AM
Great question! This will not fit into the Skimz sumps due to the top rim restricting the space needed for this to be placed in, however it is possible to modify the top covering to allow for the extra space this unit requires.
Answer by: Nick Gansen on Aug 31, 2018, 11:21 AM
Any reviews on this? Also, any idea if this will fit into a trigger 39 sump filer sock area?
Question by: William Henry on Aug 31, 2018, 8:52 AM
Thank you for contacting BRS!

We currently do not have any reviews for this Klir, but it has just released, and I would expect to see some soon. Using this with the Trigger 39 sump is possible, however you would have to modify the cover portion to make this work, as the Klir extends too high out of the sump.
Answer by: Nick Gansen on Aug 31, 2018, 10:52 AM
Will this work with a Red Sea Reefer 250 sump?
Question by: Luis Rosa on Aug 30, 2018, 5:52 PM
Hello there,

Great question! This will work with the reefer 250 assuming you do not have the glass ATO box on top of where the filter sock usually goes. There will also need to be a modification done as the Klir needs about 1.5" for the water level to rise above where the filter sock trays usually go to trigger the sensor. The reefer has 9.5" clearance and this needs 8.125" to drop down into the water. The rest of the unit will be above the water line.

Hope this helps, have a great day!
Answer by: Eric Bowman on Aug 31, 2018, 11:38 AM