DSR POWERFILTER FOR DUMMIES 
Why I Think This Is Worth Sharing
It's been quite a while since I last shared a proper DSR-related technical post here on Reef2Reef.
Over the past years, I've mostly been sharing pictures and updates of my own reef tanks, hoping to inspire others with what can be achieved in this hobby.
For those who don't know me, I'm Glenn Fong, the developer of Dutch Synthetic Reefing (DSR).
I've been developing and refining this method for many years, running my reef systems without routine water changes since 2012. Over the years, I've built and maintained numerous large, heavily stocked reef aquariums, many of them dominated by SPS corals.
Currently, I still have over 5,000 litres of reef aquariums running at home. I build all my tanks myself and design much of the equipment I use.
Experimenting, improving and finding practical solutions have always been important parts of this hobby for me.
WHY AM I SHARING THIS NOW?
I realize there's probably a whole new generation of reefkeepers here who aren't familiar with DSR or the principles behind it.
That's partly because I haven't been very active in sharing technical DSR-related topics for quite some time.
Over the years, I became somewhat more reserved about discussing my methods publicly, because technical explanations involving DSR could sometimes be interpreted as product promotion.
So I mostly let my aquariums speak for themselves.
But looking at the current state of the hobby, I've started reconsidering that approach.
The marine aquarium hobby seems to be shrinking in many places. Costs are increasing, participation appears to be declining, and I regularly see reefkeepers struggling to achieve the results they hoped for.
And let's face it: constantly battling algae, cyanobacteria, poor coral growth and unstable systems isn't exactly motivating.
When people repeatedly struggle to maintain a healthy, attractive reef, some eventually give up altogether.
That only reinforces the downward trend.
I believe fellow reefkeepers deserve better.
Knowledge and practical experience should be shared, especially when they can help people become more successful and continue enjoying this wonderful hobby.
You don't have to use DSR to benefit from the principles behind it. And you certainly don't have to agree with everything I do.
I'm simply sharing what has consistently worked for me over many years.
And some subjects are just too important to keep to myself.
LET'S START WITH SOMETHING SIMPLE: THE POWERFILTER!
One of the most important principles behind my approach is removing organic waste before it has the opportunity to break down.
It sounds obvious, yet I still see many reef aquariums where detritus accumulates between rocks, underneath coral colonies and in poorly circulated areas.
We spend a lot of time discussing nutrients, bacteria, additives and complicated filtration systems.
But what about physically removing the waste before it becomes part of the nutrient cycle?
That's where the DSR Powerfilter comes in.
It's a remarkably simple device, but one that has become indispensable in my own reef systems.
And although I developed my own version, the underlying principle is universal.
1. WHAT DOES A POWERFILTER ACTUALLY DO?
Every aquarium continuously produces organic waste:
- Fish waste and uneaten food.
- Coral mucus and shed organic material.
- Decaying algae and biological debris.
- Detritus accumulating between rocks and coral colonies.
When this material remains in the system, bacteria and other organisms gradually break it down, releasing nutrients and increasing the organic load.
A Powerfilter captures suspended particles and allows you to physically remove them before further decomposition.
The principle is simple: remove the waste instead of continuously dealing with its consequences.
2. WHY INSTALL IT DIRECTLY IN THE DISPLAY?
Many reefkeepers rely on filter socks, filter rollers or mechanical filtration inside their sump.
Those systems can work very well.
But there's one important limitation: waste must actually reach them!
In mature reef aquariums, particularly those with large SPS colonies, a considerable amount of detritus never makes it to the overflow.
It settles between rocks, underneath corals and in areas with insufficient circulation.
By placing a Powerfilter directly inside the display, suspended waste can be captured much closer to where it originates.
In my experience, this can be significantly more effective than relying exclusively on mechanical filtration in the sump.
3. HOW IS THE DSR POWERFILTER CONSTRUCTED?
The design is deliberately simple.
It consists of:
- An adjustable DC pump.
- A perforated sieve tube.
- Ordinary filter floss.
- A protective Powerfilter Guard (mesh).
- An outer shield that protects the assembly and directs water intake.
Water is drawn through the filter floss, trapping suspended particles.
No complicated technology or expensive filter media. Just efficient mechanical filtration.
PREPARING THE FILTER:
1. Take a suitable piece of filter floss.
2. Wrap it evenly around the perforated tube, preferably in three thin layers rather than one thick layer.
3. Place the protective mesh around the floss.
4. Secure the mesh with two rubber bands.
5. Insert the assembly into the shield and start the pump.
Rinsing new floss with warm water beforehand can help prevent excessive protein skimmer foaming.
Don't pack the floss too tightly. More material doesn't necessarily improve filtration.
4. HOW OFTEN SHOULD THE FLOSS BE REPLACED?
My recommendation is every 2–3 days, with 4 days as the maximum.
As particles accumulate, the floss can capture increasingly fine material.
However, leaving dirty floss in the aquarium for too long defeats the purpose.
The trapped organic waste remains in the system and continues to break down, while water flow gradually decreases.
The whole idea is to physically remove that waste, not to turn your mechanical filter into another biological waste-processing station.
5. CHOOSING THE RIGHT PUMP
I prefer adjustable DC pumps because they allow the flow to be matched to the filter.
My practical recommendations:
- Up to 200 litres: Jecod DCS1000–1200.
- Up to 1,000 litres: Jebao MCD2000 / DCP2500.
- Up to 2,000 litres: Jebao DCP3500.
- Above 2,000 litres: multiple Powerfilters.
For example, my DSRapproved Powerfilter with a Jebao DCP2500 operates very well at approximately 80% output, consuming around 19 watts.
I don't recommend conventional AC pumps for this particular application.
More pump power doesn't automatically mean better filtration.
6. WATER CIRCULATION IS JUST AS IMPORTANT
A Powerfilter can only capture waste that actually reaches it.
That's why effective circulation is essential.
The objective isn't to create the strongest possible current, but to keep detritus moving so it can be transported toward the filter.
Pay particular attention to areas underneath and behind rock structures, spaces between large coral colonies, low-flow zones near the aquarium bottom and places where detritus repeatedly accumulates.
In larger systems, multiple Powerfilters may be necessary.
7. THE LATEST IMPROVEMENT: THE DSR POWERFILTER LIGHTSHIELD
One of my more recent improvements is the Lightshield.
Besides blocking light from reaching the filter assembly, it also features an additional water intake near the bottom.
Positioning this intake approximately 1–2 cm above the aquarium floor allows the filter to collect waste from areas where detritus would otherwise accumulate.
This is particularly useful in established aquariums with large rock structures and limited circulation near the bottom.
Removing accumulated organic material helps reduce the conditions that can lead to oxygen-depleted or anoxic zones.
For systems with a significant backlog of detritus, I've found this improvement especially valuable.
8. WHAT ABOUT CYANOBACTERIA?
Whenever cyanobacteria appear, discussions often immediately focus on nitrate, phosphate or lighting.
But I believe organic waste accumulation deserves much more attention.
Detritus trapped between algae, rocks and coral colonies can create local conditions favourable to cyanobacterial growth.
My approach starts with physical removal:
1. Siphon out as much cyanobacteria and accumulated waste as possible.
2. Use the Powerfilter to capture suspended debris.
3. Improve circulation and eliminate persistent dead spots.
4. Replace the filter floss every 2–3 days.
For stubborn outbreaks, I sometimes combine this with a temporary blackout of up to three days, followed by restarting the lighting at approximately 50%.
A Powerfilter isn't a guaranteed cure for cyanobacteria, but maintaining a clean system provides a much better foundation.
9. WHY IS THIS ESPECIALLY IMPORTANT FOR ACROPORA?
As SPS colonies grow, they increasingly obstruct water circulation.
Detritus becomes trapped between branches and behind large colonies.
This is one reason I consider effective mechanical waste removal essential in my own Acropora-dominated systems.
The Powerfilter doesn't directly control alkalinity, calcium or other water parameters.
Instead, it helps reduce the organic load and supports a cleaner environment.
Combined with stable water chemistry and effective circulation, this has been a major part of my long-term success with SPS.
10. HOW DO YOU KNOW IT'S WORKING?
Don't judge a Powerfilter solely by how dirty the floss becomes.
Look at the aquarium itself.
Is less detritus accumulating? Are previously problematic areas becoming cleaner? Is the water visibly clearer?
One simple check I use is the white bucket test.
Fill two white buckets with approximately 20 cm of water, one with aquarium water and the other with clean reference water. Compare them under natural daylight.
This helps reveal yellowing that may otherwise be difficult to notice.
Keep in mind that mechanical filtration removes particles, not dissolved colour compounds.
11. WHAT A POWERFILTER DOESN'T REPLACE
A Powerfilter is not a substitute for proper water chemistry, circulation or an effective cleanup crew.
I still consider regular testing of KH, Ca, Mg, K, NO3, PO4 and especially salinity in ppt essential.
Successful reefkeeping is about making all the important elements work together.
FINAL THOUGHTS
I've been running DSR reef aquariums without routine water changes since 2012.
One of the most important lessons I've learned is that preventing pollution is often much easier than correcting its consequences.
The Powerfilter is a good example.
It doesn't require sophisticated equipment or expensive consumables.
It comes down to three basic principles:
1. Keep waste moving.
2. Capture it efficiently.
3. Physically remove it before it breaks down.
That's really all there is to it.
Over the years, this simple approach has become indispensable in my own large, heavily stocked SPS systems.
I realize that many reefkeepers have developed their own successful approaches, and that's perfectly fine. I'm not suggesting there's only one way to maintain a beautiful reef.
But I do believe that sharing practical experience is more valuable than keeping it to ourselves.
Especially at a time when our hobby could use more successful, motivated reefkeepers.
Hopefully, this will be useful to some of the newer members who haven't come across DSR before.
And perhaps it will encourage a few experienced reefkeepers to take another look at something as simple as mechanical waste removal.
I'm curious how others approach detritus management in mature reef tanks. Do you rely entirely on sump filtration, or do you also remove waste directly from the display?
Happy reefing!
Glenn Fong
Dutch Synthetic Reefing (DSR)
Closing a Chapter… 1,300 Litres Less!
