Pureflow Bio · Freshwater treatment
Freshwater Protein Skimmer
Manufactured in India for freshwater ponds, hatcheries, aquariums and RAS projects.
First, compare nine PSF models from 5 to 150 m³/h. Then select around your water conditions and treatment needs.
Pair the skimmer with a microscreen drum filter and biological treatment as part of your filtration system.
What Is a Freshwater Protein Skimmer?
A freshwater protein skimmer uses foam fractionation. First, it brings air and water into contact to collect foam-active organic matter and associated fine particles. Then it separates that material into a waste stream.
Applications
Freshwater Protein Skimmers for Koi Ponds, Hatcheries and RAS
Koi ponds
Evaluate a protein skimmer for koi pond filtration alongside mechanical solids removal and biological treatment.
Best for: Pond owners and builders assessing foam-active organic loading.
Ornamental fish breeding
Before selecting a skimmer, review species requirements, feeding levels and the layout of your filtration loops.
Best for: Breeding facilities planning an additional organic-waste separation stage.
Hatcheries
For example, match the treatment arrangement to the species, life stage and water conditions.
Best for: Hatchery operators evaluating freshwater foam fractionation.
RAS farms
Assess a protein skimmer for RAS using daily feed load, treatment flow and the existing filtration process.
Best for: Farm operators reviewing organic-waste management in a recirculating loop.
Aquaponics
However, check the proposed removal stage against the system’s fish and plant nutrient objectives.
Best for: Growers assessing whether foam fractionation suits their treatment strategy.
Aquariums
In addition to exhibit requirements, allow space for drainage and maintenance access.
Best for: Aquarium operators and contractors integrating freshwater treatment equipment.
The process
How a Freshwater Protein Skimmer Works
Foam fractionation creates an air–water interface where foam-active material can collect. As bubbles rise, the resulting foam is separated from the treated water and directed to a waste collection arrangement.
Freshwater generally produces less stable foam than saltwater, making foam fractionation more challenging and often less effective under comparable conditions. To support air–water contact, the Pureflow PSF catalogue describes continuous fine-bubble generation for freshwater applications.
Consider skimming when foam-active organic material is a defined treatment concern. However, it complements microscreen drum filtration and biological treatment; it does not replace either stage.
Bring water and bubbles into controlled contact.
Collect foam above the treatment zone.
Route collected material to suitable drainage.
Equipment and project planning
PSF Skimmer Features and Benefits
Nine PSF models
Compare flow ratings from 5 to 150 m³/h as a starting point for equipment selection.
Published dimensions and connections
Before planning the pipework, check body sizes and inlet/outlet diameters against the available space.
Model-specific power figures
Listed power from 0.2 to 2.2 kW includes all pumps supplied with each skimmer. Also confirm electrical requirements for any optional accessories.
Fine-bubble generation
The catalogue describes continuous fine bubbles for air–water contact. However, actual separation depends on operating conditions.
Customization available
Define the required configuration around your project’s installation and treatment requirements.
Indian manufacturing and turnkey capability
Review equipment supply and complete-system integration with Pureflow Bio.
A closer look
Freshwater Protein Skimmer Gallery
Explore the equipment views and component details below. Then select an image to enlarge it.
Collection chamber
Pump and control panel
Pond setting
Front arrangement
Pipework detail
Angled equipment view
Renders and illustrations show equipment concepts. However, the supplied equipment and accessories depend on the approved configuration.
Technical selection
PSF Freshwater Protein Skimmer Models and Specifications
Compare nine freshwater protein skimmer models with catalogue flow rates from 5 to 150 m³/h. Next, review the project checklist below to confirm suitability and installation requirements.
PSF model specifications
| Model | Diameter × height mm | Water flow m³/h | Inlet mm | Outlet mm | Power kW | Voltage V | Vessel Material |
|---|---|---|---|---|---|---|---|
| PSF-5 | 450 × 1500 | 5 | 32 | 50 | 0.2 | 110/220 | Polypropylene (PP) |
| PSF-10 | 500 × 2100 | 10 | 32 | 75 | 0.3 | 110/220 | Polypropylene (PP) |
| PSF-15 | 550 × 2100 | 15 | 50 | 90 | 0.37 | 110/220 | Polypropylene (PP) |
| PSF-20 | 680 × 2200 | 20 | 50 | 110 | 0.6 | 110/220 | Polypropylene (PP) |
| PSF-30 | 750 × 2500 | 30 | 63 | 110 | 0.75 | 110/220 | Polypropylene (PP) |
| PSF-50 | 900 × 2800 | 50 | 75 | 160 | 1.1 | 110/220 | Polypropylene (PP) |
| PSF-80 | 1100 × 3000 | 80 | 75 | 160 | 1.5 | 110/220 | Polypropylene (PP) |
| PSF-100 | 1200 × 3200 | 100 | 110 | 160 | 1.85 | 110/220 | Polypropylene (PP) |
| PSF-150 | 1500 × 3300 | 150 | 110 | 200 | 2.2 | 110/220 | Polypropylene (PP) |
Models shown are for reference. However, customization is available to suit project requirements. Body dimensions are diameter × height in millimetres. All nine models have a polypropylene (PP) vessel. Listed power includes all pumps supplied with each skimmer. Finally, confirm the configuration, electrical supply and operating duty in your quotation.
Optional components
Specify the options you need in your enquiry. Availability, compatibility and scope are confirmed for the selected PSF model and project. However, these items are not included in the basic equipment unless expressly stated in your quotation.
| Component or specification | Details to confirm |
|---|---|
| Electrical control panel | Electrical configuration and panel scope. |
| Electrical control panel footprint (mm) | Dimensions and mounting arrangement to be confirmed for the selected configuration. |
| Motorized foam collector autowash | Cleaning arrangement and controls. |
| Overflow switch | Switch location and interlock requirements. |
| ORP control | Probe, controller and control scope. |
| Foam level automation | Level sensing and automation scope. |
| Operational platform | Platform dimensions and access arrangement. |
| Passive ozone destruct | Compatibility and ozone treatment duty. |
| Quick retractable ORP/pH probe fitting | Probe and fitting compatibility. |
| PS venturi pump | Pump duty and electrical requirements. |
| Ozone gas rotameter | Gas flow range and connection sizes. |
| Outer wash port and valve for chemical dosing | Connection arrangement and chemical compatibility. |
| Reuse of off-gassed ozone | Engineered gas routing, residual control and safety requirements. |
| Sight glass | Size, position and material. |
| Manhole with PP cover | Opening size, position and sealing arrangement. |
| Manhole with acrylic cover | Opening size, position and sealing arrangement. |
| Ozone inlet solenoid valve with SS 316 body | Valve size, voltage and ozone compatibility. |
| PS camera | Camera specification and monitoring arrangement. |
| PS PLC controller | Control functions, inputs/outputs and integration scope. |
Control-panel dimensions and model-specific availability are confirmed in the quotation. In addition, ozone-related options require a complete treatment and safety review.
Specifications
We aim to keep all product information accurate and current. However, specifications may change as products are updated. Before ordering, please confirm the latest technical details, electrical requirements for your region with our team.
Displayed specifications cover the basic equipment only. In addition, optional components are quoted separately unless expressly included. Your quotation confirms the final configuration, scope of supply and delivery terms.
Project specification checklist
| Hydraulic duty | Design flow, operating water level, inlet and outlet conditions, head requirement and proposed treatment arrangement. |
|---|---|
| Treatment conditions | Water temperature, salinity, organic loading, feed input and the agreed treatment objective. |
| Air and contact system | Bubble-generation method, air requirement, contact arrangement and adjustment range. |
| Dimensions and connections | Overall height, footprint, service clearance, inlet, outlet, drain and foam-waste connections. |
| Materials | Polypropylene (PP) vessel across all nine models. Confirm pipework, seals and compatibility with the actual water chemistry and cleaning method. |
| Pump and electrical supply | Selected pump, duty point, installed power, voltage, phase, frequency and control-panel scope. |
| Collection and cleaning | Foam collection, drainage, inspection access and the cleaning arrangement supplied. |
| Controls and accessories | Included instruments, level controls, alarms, interlocks and any separately quoted options. |
| Documentation and supply | Model data sheet, arrangement drawing, operating instructions, commissioning scope and delivery terms. |
Catalogue specifications are shown above. Final equipment selection, customization and scope are confirmed in the quotation for your application.
System integration
Integrating a Skimmer into Your Freshwater Filtration System
A protein skimmer complements mechanical filtration and biological treatment. However, it does not replace either stage.
- Agree the connection point and treatment flow.
- Check available head, return conditions and drainage.
- Allow access around pumps and collection components.
- Define monitoring, cleaning and commissioning responsibilities.
If ozone is proposed
Design the complete treatment arrangement
All nine PSF models operate without ozone and support optional ozone integration. However, any ozone installation needs appropriate dosing and residual control, off-gas treatment, ventilation and interlocks.
Ask which components are included in the quotation and how the system will be commissioned.
Discuss ozone contact equipment ↗Engineering & procurement
Freshwater foam fractionation: how to judge suitability
Freshwater skimming can collect foam-active material, but the result depends on the water and the air–water contact arrangement. Specify the separation objective before choosing a PSF model.
Define a result that can be checked
Record the incoming water conditions, feed load, treatment flow and operating settings. Agree what will be monitored during commissioning: foam collection, organic-load measurements where specified, water clarity and maintenance observations. Appearance alone is not a verified removal percentage.
Keep each treatment stage accountable
A drum filter screens suspended solids; a biofilter supports ammonia conversion; a freshwater fractionator separates material carried into foam. Combining those stages does not make their duties equivalent or guarantee a particular tank carrying capacity.
| Selection item | Specify or verify | Why it changes the selection |
|---|---|---|
| Foam behaviour | Conductivity or salinity, temperature, pH and foam-active loading | Freshwater conditions can produce less stable foam than marine conditions. |
| Air–water contact | Actual through-flow, injected air, operating level and contact geometry | These determine the process conditions that a flow listing alone does not describe. |
| Electrical schedule | Model power listing, supplied pump scope and optional accessories | Rated input and measured average energy use are different quantities. |
| Commissioning record | Baseline conditions, agreed observations, sampling method and operating settings | Repeatable observations help distinguish equipment operation from changing feed and water conditions. |
For marine water, compare the separate PSM saltwater protein skimmer range.
Discuss the technical requirements →Equipment selection
How to Size a Freshwater Protein Skimmer
Start with the material you want to remove and the water you need to treat. Next, review flow, feed load, water chemistry and the proposed installation.
A model’s flow rating does not establish a suitable tank volume by itself. Therefore, avoid choosing solely from pump flow or pond volume.
Information needed for selection
- Application, species and total water volume.
- Daily feed load and proposed skimmer flow.
- Salinity or conductivity, temperature and pH, if measured.
- Existing filters, pumps, UV and ozone equipment.
- Available space, water levels and drainage.
- Electrical supply, project location and treatment objective.
Find a starting model
Freshwater Protein Skimmer Model Selector
Enter your planned skimmer flow to find a PSF catalogue candidate and its dimensions, connections and power.
Still planning the flow? Use your system volume and a skimmer-loop turnover time specified for your project. Alternatively, send your requirements for sizing if you do not know either.
How the selection works
Planned flow: use the actual flow through the skimmer, not the main circulation pump’s nameplate flow.
Volume method: Q = V ÷ T, where Q is skimmer-loop flow in m³/h, V is system water volume in m³ and T is your specified equivalent turnover time in hours. There is no default turnover time. This hydraulic calculation does not predict removal efficiency.
The selector returns the smallest published PSF flow rating at or above Q within 5–150 m³/h. Catalogue ratings are selection references, not verified operating ranges; confirm allowable flow and pump duty before ordering. However, flows outside this range need a custom or parallel-system review.
Contact time is a different calculation: nominal hydraulic residence time in seconds = 3,600 × active water volume inside the skimmer (m³) ÷ flow (m³/h). Overall vessel dimensions do not establish active water volume. Therefore, we do not infer contact time or feed capacity from them.
Research background: freshwater foam fractionation research (DTU, 2021) and effects of operating conditions in seawater RAS (2023). However, these studies do not validate Pureflow model capacities.
Send your requirements
Request a Freshwater Protein Skimmer Quote
Share your preferred PSF model, flow and water conditions. We reply within 1 business hour.
Supply and support
Warranty, dispatch and installation.
1-year warranty
From the invoice date, covering the complete skimmer, including the vessel, pump and electrical components.
15 working days
Standard-model dispatch after order confirmation.
Installation across India
Installation and commissioning are available across India, with the scope defined in your quotation.
Warranty exclusions: Normal wear, dry running, voltage damage, improper operation and physical damage.
Practical answers
Freshwater protein skimmer FAQs.
Do protein skimmers work in freshwater?
Yes, though they behave differently. Freshwater makes less, wetter foam than seawater, so a freshwater skimmer is designed around a taller contact column and finer bubbles. The foam may look modest, but it still pulls out fine particles, dissolved organics and bacteria.
What does a freshwater skimmer remove that my filter doesn't?
It removes the very fine particles and dissolved proteins that slip through a drum screen and slowly turn water cloudy or yellow. Taking them out early means less ammonia and nitrate later, and less load on your biofilter.
Why doesn't my freshwater skimmer make much foam?
That's normal. Freshwater has a different surface tension, and foam forms more readily in water with more dissolved organics and minerals. Lower foam doesn't mean it isn't working. Adding ozone to the skimmer usually boosts foam and performance considerably.
Where does a skimmer go in a RAS or koi system?
Usually on a side stream after the drum filter, so it isn't loaded with coarse solids, and before the biofilter or on a loop around it. It also makes an excellent place to dissolve ozone.
How is a freshwater skimmer sized?
By the flow through it and the organic load, which comes mostly from your daily feed. Heavily fed fish farms need more skimmer capacity than a lightly stocked koi pond of the same volume. Tell us your feed rate and flow and we'll suggest a model.
How much maintenance does it need?
Empty or flush the foam collection cup regularly, or fit a foam extractor so it's handled automatically. Keep the air injector clear, as scale and slime gradually reduce air intake.
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