The Importance of your Filtration System

Zebrafish are extremely valuable model organisms for research, however there is additional work, knowledge, and skills that is required to properly care for these tropical fish within a lab or facility. As rigor and reproducibility is critical in research, especially in the biomedical sector, providing optimal and stable conditions for zebrafish is important for overall fish health and therefore ensuring the needs of the researchers are being supported. This means creating a system in place for the fish which considers all environmental parameters and having the correct filtration components from a biological, chemical, and mechanical aspect.

Along the lines of investing in high-quality products for your system – investing in experienced and skilled individuals to manage your zebrafish room/facility is equally as important. Furthermore, in addition to technicians, you might inevitably find yourself needing more extensive technical service and support. At Danio Lab, one of our core services is Danio Care, where we offer multiple-level zebrafish care plans. We provide customized services and support for zebrafish labs and facilities of all different sizes and levels. Zebrafish life support systems are our bread and butter. Dialing in your water quality parameters through a proper filtration system is key in maintaining the overall health of your colonies.

Filtration | Mechanical, Biological, Chemical

Before the water is delivered to a zebrafish rack, it must be treated in multiple stages to ensure it’s clean for your fish. Once it has undergone the proper treatment, it can be returned to your fish tanks/racks. These various filtration elements are all interconnected and translate into superior, long-term water quality parameters throughout your fish racks.

Water Quality Parameters to Monitor:

• Ammonia, Nitrite, Nitrate
• Temperature
• Salinity
• Dissolved Oxygen
• Carbon Dioxide
• Alkalinity
• Hardness 

Some General Elements of Water Filtration

• Bead filter
• Drum filter
• Sump
• Water Pump
• UV sterilizer

Bead Filters

A bead filter is an efficient unit and method for solids removal and promoting nitrifying bacteria in RAS (recirculating aquaculture systems), especially in regarding to zebrafish facilities. Typically, they can remove solids down to around 50 microns. Basically, the beads trap solids, water flow within the unit slows down, beads get stirred, and the solids fall to the bottom of the unit to settle, where they are then drained out. In addition to solids removal, the beads also facilitate bacteria (nitrifying) to colonize via providing a substrate (surface area).

Advantages

• Superior solids removal/clarification
• Energy efficient
• Long-lasting and easy maintenance
• Biofiltration capabilities

Poly-bead, Biomechanical Clarifier

At Danio Lab, as part of our filtration skids, we are going to be incorporating a poly-bead biomechanical clarifier that uses air (instead of water) to backwash which reduces water usage and makes for a more sustainable product. Reach out to us for more information.

Drum Filter

Drum filters are high-performance, self-cleaning filtration units that remove solids while reducing the amount of particulate matter that gets broken up. In simple terms, the water is directed through a screen, which collects the solids, and then a built-in backwashing mechanism washes the compiled solids into a draining outlet. Thereafter, the unit goes back to regular filtering mode and the self-enacting mechanism is repeated as solids accumulate. This is a great component of a filtration system as it cuts down on reliance on monthly/yearly consumable items (such as filter pads/bags), hence increasing the sustainability of operations and lowering our impact on the environment.

Advantages

• Self-cleaning, automated features
• Very efficient
• Sustainable
• Cost-effective long-term

Biological Filtration

In general, biological filtration is the process of controlling and treating ammonia nitrogen produced via fish excretions and leftover food. In other science terms – oxidation of ammonia to nitrite to nitrate (via nitrifying bacteria). These bacteria exist on substrates/surfaces you provide them with such that it’s essential that these populations of bacteria remain healthy. Their health is interconnected with all other water quality parameter such as temperature, salinity, alkalinity, and dissolved oxygen. A well-designed filtration system should be designed to ensure oxygenation remains high.

There are mainly three types of biofiltration that are commonly utilized in aquaculture systems

• Fluidized bed reactors
• Moving bed bioreactors
• Trickling media

Chemical Filtration

Post-biological filtration, system water is usually passed through a type of chemical filter (such as activated carbon or charcoal bags), that can pick up/absorb substances that might not have been caught (or couldn’t be filtered) in prior stages – so you can look at this as a finishing stage. This type of filtration is pretty cost-effective and can be useful is removing unwanted contaminants from your system.

UV Sterilization

UV sterilizers are able to produce short wavelengths that are able to disinfect water by killing (essentially damaging their DNA structure) microbes such as bacteria and viruses. The setting (or zap dose) of your UV sterilizer can depend on some factors such as the actual power of your specific UV unit, clarity of the water, microbial levels present, and the amount of time/contact the water spends with the lamp. These lamps are typically placed in a quartz sleeve and water is exposed to the UV, where it is then thereby disinfected and ready to move along to the next filtration stage (which is commonly back to your rack system).

Advantages

• Incredibly effective sterilization method
• Safe to operate
• Unharmful to zebrafish

System Monitoring & Control Panels

We believe having a centralized control panel to complement your filtration system can be incredibly effective to easily and accurately track water quality factors such as pH, conductivity, and temperature. At Danio Lab, we offer a self-intuitive, complete digital monitoring system that is integrated onto our filtrations skids, so that all your information is centralized and accessible all in one place.

Control panels are also advantageous because they can include a notification and alarm system, which can be beneficial at letting team members know if preset parameters change too quickly or drop below your desired range. The system can be customized, and alarms can be generated to let users know what exactly the issues are. Some monitoring units provide real-time data to current system parameters, so you can log in to view data anywhere at any time.

Advantages

• Automatically tracks & monitors key parameters
• Digitally, easy to read display
• Alarms/notification settings
• Makes calibration & recording easier

Danio Lab’s Products & Services

At Danio Lab, we offer our own custom zebrafish filtration skids (Danio ZFS-VSA, to accompany our Danio Housing System), filtration system & component upgrades, system maintenance &troubleshooting solutions, repairs & replacement parts. We install complete filtration units, provide technical support, upgrade systems, deliver replacement parts, and provide training and consultation for individuals looking for assistance with their operations.

We have over 20+ years of experience in the industry developing solutions for zebrafish facilities, institutions, hospitals, and universities across the globe. As a one-stop-shop for all your zebrafish husbandry needs, we offer maintenance programs, installation services, and technical consulting for designing or maintaining systems.

 Learn more on our website

References

Lawrence C, Mason T. Zebrafish housing systems: a review of basic operating principles and considerations for design and functionality. ILAR J. 2012;53(2):179-191. doi:10.1093/ilar.53.2.179