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RK2 saltwater protein fractionators

RK2 Saltwater Protein Fractionators (also called foam fractionators or protein skimmers) are filtration devices that remove suspended particulates, dissolved organics, proteins and tints. At the same time, protein fractionation lowers bacteria and pathogen concentrations, while saturating the water with oxygen. Traditional water filtration systems, (i.e: pressurized sand filters, bead filters and cartridge filters), remove particulates but are ineffective against dissolved wastes and act as breeding grounds for bacteria and pathogens.

Water that is filtered through traditional filters is constantly sieved through the trapped wastes. Similar to that of a tea bag, this action leaches bacteria, dissolved organics and tints back into the water. The media in the filter functions as a bio-filter, promoting bacteria, which in turn strip out oxygen. Consequently, the discharge from these filters is generally enriched with bacteria and dissolved organics as well as having reduced oxygen concentration.

When using RK2 Saltwater Protein Fractionators, the fractionation filtration process is simple and highly effective. Air, (in some cases ozone as well), are injected into the bottom of the reaction chamber via an ozone resistant venturi injector. The water to be filtered is introduced at the top of the chamber and exits at the bottom. This creates a mass mixing effect, with the water traveling cross current to the air, which is essential for the effective formation of foam. The foam rises through the column and becomes more concentrated as it passes into the upper rise tube. The tube allows for the water to drain back into the tank via gravity, while the concentrated foam is ejected over the top of the riser tube and collected into a waste drain. The upper chamber is automatically washed down with rinse systems that keep the surfaces clean and prevent the foam from drying and inhibiting the ejection process.

How Ozone and Protein Fractionation Works Together

Ozone Injection enhances the fractionation process in a number of ways. Ozone oxidizes various pathogens, from bacteria to viruses. Ozone is extremely effective on organic water tints creating crystal clear water. Ozone also breaks down the structure of larger organic molecules, which facilitates their removal by fractionation. Being a three-part oxygen molecule, ozone dramatically increases oxygen concentration. Ozone in doses appropriate for aquaculture is very safe.

The fractionation and ozone combination is extremely effective in a variety of applications. Grow out tanks and aquaria displays with heavy bio-loads become remarkably cleaner. Clean Systems, such as larval rearing or holding tanks can become crystal clear. Protein fractionation with ozone is excellent for systems with heavy mucous concentrations such as closed or semi open finfish and shellfish holding systems. Other applications include purging systems, grow out systems, effluent treatment as well as influent water treatment for use within partial and full flow thru systems.

The protein fractionation process increases water clarity and oxygen concentration, and also destroys and removes pathogens. Consequently, appetite, stocking densities, feed and growth rates are all enhanced and animal health improved.

Used within aquaculture, live seafood holding as well as most public aquariums worldwide, RK2 Saltwater Protein Fractionators are an essential component within any aquatic life support filtration system. Protein fractionation is effective in seawater, freshwater as well as brackish water systems, within partial or full flow applications. Individual models are available with processing flow rates from 3 to 2000 gallons per minute. For larger flow rate applications, our protein fractionators can be incorporated into any modular system design, thus allowing us to process any system volume where protein fractionation is required.


MOLDED HDPE SCREW TOP LID – Allows for easy maintenance access


BAFFLE SYSTEM IN TOP CONE – Creates stilling action to maintain foam structure and laminar ejection

AUTOMATED DUAL WASH DOWN ASSEMBLIES – Electronic or battery operated control allows simple, unlimited configurations of rinse time and interval cycling

CLEAR SIGHT GAUGE – Makes adjusting water level height inside filter simple

ACRYLIC & MOLDED HDPE REACTION CHAMBERS – with no tube wall penetrations

KYNAR VENTURI INJECTORS – Standard on all units for injection of ozone gas

TUNED VENTURI PUMPS – Provide excellent flow to amp draw design

MULTIPLE MASS MIXING FEATURES – Unique “charging points” enhance and increase gas – liquid interface

316 STAINLESS STEEL HARDWARE – Made with the highest quality non-corrosive components

Model Flow Rate Diameter Venturi pump Height Footprint Operational weight Dry Weight
RK10AC 35-75 LPM 25.4 CM 1/6 HP PUMP
230 VAC, 1 PH
215.9 CM 38.1 X 91.44 CM 124.73 KG 45.35 KG
RK25PE 76-133 LPM 35.56 CM 1/6 HP PUMP
230 VAC, 1 PH
195.58 CM 60.96 X 91.44 CM 200 KG 47 KG
RK50PE 152-228 LPM 50.8 CM 1/2 HP PUMP
230VAC, 1 PH
251.46 CM 81.28 X 86.36 CM 477 KG 100 KG
RK75PE 265-398 LPM 60.96 CM 1 HP PUMP
230 VAC, 1 PH
259.08 CM 81.28 X 86.36 CM 636 KG 107 KG
RK75PE-HF 398-530 LPM 60.96 CM 1.5 HP PUMP
230 VAC, 1 PH
259.08 CM 81.28 X 86.36 CM 636 KG 107 KG
RK150PE 587-871 LPM 91.44 CM 1.5 HP PUMP
230 VAC, 1 PH
256.54 CM 104.14 X137.16 CM 1352 KG 166 KG
RK150PE-HF 871-1,174 LPM 91.44 CM 1.5 HP PUMP
230 VAC, 1 PH
256.54 CM 104.14 X 137.16 CM 1352 KG 166 KG
RK300PE 1,098-1,647 LPM 121.92 CM 1.5 HP PUMP
230 VAC, 1 PH
279.40 CM 137.60 X 167.64 CM 2305 KG 200 KG
RK300PE-HF 1,647-2,196 LPM 121.92 CM 2 HP PUMP
230 VAC, 1 PH
279.40 CM 137.60 X 167.64 CM 2305 KG 200 KG
RK600PE 3,370-4,505 LPM 152.4 CM (2) 1.5 HP PUMPS
230 VAC, 1 PH
365.76 CM 175.26 X 198.12 CM 4847 KG 341 KG
RK600PE-HF 3,370-4,505 LPM 152.4 CM (2) 2 HP PUMPS
230 VAC, 1 PH
365.76 CM 175.26 X 198.12 CM 4847 KG 341 KG
RK1000PE 4,164-6,246 LPM 213.96 CM (4) 1.5 HP PUMPS
230 VAC, 1 PH
365.76 CM  233.68 X 289.56CM 9242 KG 409 KG
RK2000PE 5,679-7,571 LPM 213.96 CM (4) 2 HP PUMPS
230 VAC, 1 PH
426.72 CM 238.76 X 289.56 CM 11,585 KG 545 KG
* = HF models operate at higher flow rates and reduced contact times
**Pro Series Models are available at an additional cost. Pro Series includes – schedule 80 PVC plumbing, Hayward True Union Ball Valves, Electronic Wash Down Assemblies and bulkhead fittings