Chezur
Aquarium filtration without magic numbers
Connect flow, media capacity, livestock and maintenance instead of relying on one headline rate.
What you will find
- Choose a filter type
- Allow for real-world losses
- Maintain biological stability
Editorial catalogue
Product profiles and comparisons
Fifteen dossiers based on official documentation. Open a profile to check capacity, limitations and alternatives before buying.
Documentary profile
EHEIM classic 250 documentary profile
How to assess the stated 80–250 L range and 440 L/h nominal flow, cross-check a simple layout without an integrated prefilter and manual priming and make a decision from rated power, media volume and replacement-part access.
Read profile →Documentary profile
EHEIM ecco pro 300 documentary profile
How to assess the stated 160–300 L range and 750 L/h rating, cross-check three baskets, a prefilter and multifunction handle and make a decision from the stated 8 W against footprint and seal complexity.
Read profile →Documentary profile
EHEIM biopower 240 documentary profile
How to assess a modular internal filter stated for 160–240 L, cross-check adjustable flow and a ball-mounted directional outlet and make a decision from separable baskets that support staggered servicing.
Read profile →Documentary profile
Fluval 207 documentary profile
How to assess the European stated range of 60–220 L, cross-check media baskets, vertical foam block and valve assembly and make a decision from cabinet footprint, head height and service access.
Read profile →Documentary profile
Fluval 307 documentary profile
How to assess the stated 90–330 L range, cross-check greater capacity and nominal flow than the 207 in the 07 family and make a decision from dimensions, actual current and consumable cost in the decision.
Read profile →Documentary profile
Fluval 407 documentary profile
How to assess the stated European range of 150–500 L, cross-check top position in the 07 family and media capacity and make a decision from actual flow, head and livestock-appropriate current.
Read profile →Documentary profile
Fluval FX4 documentary profile
How to assess the commercial rating up to 1000 L, cross-check the large body, purge and FX-family water path and make a decision from space, filled weight, hoses and servicing effort.
Read profile →Documentary profile
AquaClear AC50 documentary profile
How to assess the stated 76–190 L range, cross-check an open basket and top access in a hang-on-back filter and make a decision from water level, restart behaviour and rear clearance.
Read profile →Documentary profile
AquaClear AC70 documentary profile
How to assess the stated 152–265 L range, cross-check a larger body and flow than the AC50 and make a decision from rim clearance, waterfall noise and chosen media.
Read profile →Documentary profile
AquaClear AC110 documentary profile
How to assess the stated 227–416 L range, cross-check the largest AC body and high nominal circulation and make a decision from hanging weight, level, clearance and return distribution.
Read profile →Comparison
EHEIM classic 250 versus ecco pro 300
How to assess classic simplicity versus ecco baskets and prefilter, cross-check 440 versus 750 L/h ratings and different tank ranges and make a decision from footprint, priming, access and the seals you will maintain.
Read profile →Comparison
Fluval 207 versus 307
How to assess stated 60–220 and 90–330 L ranges, cross-check differences in body, capacity and circulation and make a decision from bioload and available cabinet space.
Read profile →Comparison
Fluval 307 versus 407
How to assess stated 90–330 and 150–500 L ranges, cross-check the step in capacity, flow and dimensions and make a decision from useful reserve without excessive current or cabinet size.
Read profile →Comparison
AquaClear AC50 versus AC70
How to assess stated 76–190 and 152–265 L ranges, cross-check basket, flow and hanging-weight differences and make a decision from water level, current and rear clearance.
Read profile →Comparison
Canister versus hang-on-back filter by constraint
How to assess closed capacity and hoses versus top access, cross-check leak exposure, waterfall noise and available space and make a decision from the maintenance routine you can perform consistently.
Read profile →Filtration fundamentals
What an aquarium filter actually does: a waste pathway, not a reset button
Follow waste from the tank, through mechanical capture and biofilm, to the maintenance actions that finally remove it.
Mechanical filtration and clear water: choose capture without choking flow
A practical guide to coarse prefilters, fine polishing media, particle pathways and the maintenance cost of clearer water.
Biological filtration is living capacity, not a box of ceramic media
Understand nitrifying biofilm, usable surface, oxygen delivery, cycling and why adding media does not instantly add capacity.
Activated carbon and resins: use chemical media with an exit plan
Choose chemical filtration by target compound, capacity and stopping condition rather than treating it as compulsory filter furniture.
A bigger filter will not fix these aquarium problems
Separate filtration failures from temperature, behaviour, stocking, disease, nutrient export and circulation problems.
Filter sizing
How to size an aquarium filter: a five-decision method
Turn livestock, feeding, waste, flow tolerance and maintenance access into a filter specification you can verify.
Gross, net and system volume: use the right litres for the decision
Calculate interior water volume, account for displacement, and avoid using the marketing capacity for dosing or turnover.
Bioload is a flow of waste, not a fish-per-gallon score
Use adult biomass, feeding and waste characteristics to plan mechanical capture, biofiltration and oxygen margin.
Rated versus actual filter flow: run a bucket test
Understand head, hose resistance and loaded media, then measure a repeatable operating flow instead of guessing from the box.
Aquarium turnover rate: useful ratio, incomplete verdict
Calculate real turnovers per hour and understand why the ratio cannot represent media capacity, flow distribution or animal comfort.
Main filter types
Canister filters: useful media volume with an external plumbing responsibility
Decide when a canister earns its space and manage head loss, hoses, seals, leaks and solids before they become problems.
Internal power filters: compact independence at the cost of tank space
Use submerged filters well by matching media capacity, intake safety and directional flow to small or support aquariums.
Hang-on-back filters: easy access, water-level dependence and restart testing
Make the most of top-access media while controlling waterfall noise, evaporation, intake risk and power-cut recovery.
Air-driven sponge filters: gentle intake, biofilm and practical redundancy
Understand airlift flow, foam maintenance and back-siphon protection for fry, shrimp, quarantine and backup systems.
Canister vs internal vs HOB vs sponge: choose by failure mode and maintenance
Compare mainstream aquarium filters by media, access, current, footprint and risk instead of looking for a universal winner.
Special filtration systems
Aquarium sumps: design the power-off test before the chambers
Plan drainage reserve, overflow redundancy, return volume and top-off limits so extra water volume does not become flood risk.
Undergravel filters: when the substrate becomes both media and maintenance
Understand plate flow, gravel sizing, reverse-flow variants and the access tradeoff beneath a planted or decorated tank.
Wet–dry trickle filters: oxygen-rich biofilm with evaporation attached
Use exposed trickling media deliberately by managing solids, wetting distribution, degassing, noise and humidity.
Aquarium UV sterilisers: only the exposed water receives a dose
Separate lamp wattage from delivered dose and account for flow, turbidity, sleeve fouling and organisms outside the reactor.
Protein skimmers: what foam fractionation exports from marine water
Understand bubble-surface capture, wet versus dry foam, salinity dependence and why skimming is not complete nutrient control.
Filter media
Filter media order: map the water path before stacking trays
Arrange coarse capture, polishing, biological support and target media by actual flow and service access.
Foam and floss: choose particle capture without choking the filter
Match pore size, compression and cleaning interval to the clarity outcome instead of filling every gap with fine media.
Ceramic rings and biomedia: usable surface beats headline surface
Evaluate flow, oxygen, fouling and durability rather than incomparable surface-area claims.
Activated carbon: give it a job, a start date and an exit
Understand finite adsorption, prefiltration and conflicts with medication or additives before making carbon permanent.
Zeolite and resins: select target media from a measured target
Separate ion exchange and adsorption from biofiltration, then monitor capacity instead of hiding the underlying load.
Installation and hydraulics
Filter inlet and outlet placement: build a waste path
Prevent hydraulic short circuits and move surface water and debris through the occupied display.
Head, hose and elbows: where rated filter flow disappears
Understand static and friction head, then simplify the circuit before buying a larger pump.
Spray bar, lily pipe or nozzle: turn flow into useful current
Compare outlet area, velocity, surface motion and animal tolerance instead of judging by appearance.
Two aquarium filters: redundancy requires independent failure paths
Use duplicate units for coverage, alternating service or backup without doubling complexity blindly.
Hide aquarium equipment without hiding maintenance access
Use screens, plants and cabinetry while preserving open area, ventilation, hose radius and inspection.
Technology-specific maintenance
Clean a canister filter without losing prime or colonised capacity
Close, carry, clean, seal and restart an external filter with leak and flow checks.
Clean an internal filter without dumping its load back
Use underwater containment, safe removal, foam and rotor service, then restore immersion and direction.
Clean a HOB without making cartridge replacement the whole method
Service intake, impeller and mechanical stage while retaining permanent biological surface.
Clean an air sponge filter for flow, not showroom colour
Open the foam while separately diagnosing air pump, tube, check valve and diffuser.
How often to clean a filter: build an evidence-based interval
Use actual flow, bypass and captured load to create a tank-specific trigger.
Components and materials
Clean filter hoses to recover the diameter you paid for
Remove biofilm and deposits without damaging connectors or leaving cleaning residue.
Inspect the impeller before blaming the filter motor
Find grit, scale, shaft, bush and blade damage that causes failed starts, noise or low flow.
O-rings and seals: prevent the leak before closing the filter
Clean, inspect, seat and replace elastomers using only compatible parts and lubricant.
Clean, keep or replace filter media by function
Retain useful biofilm while discarding collapsed consumables and exhausted target media.
Prime and restart a filter without running the pump dry
Fill, valve, head and air checks for canisters and HOBs after maintenance.