D-D 39/80w Replacement Quartz Sleeve RUW256
£54.99
Freshwater Filtration
Charterhouse Aquatics stocks freshwater aquarium filtration, from external canister filters and internal filters to sponge filters, filter media and tubing. The range covers trusted freshwater filter brands including Eheim, Fluval, Oase, TMC and D-D. The right aquarium filter keeps your tropical or coldwater fish tank clean, clear and full of healthy beneficial bacteria.
Freshwater Aquarium Filtration Explained
A Complete Guide
Eheim skim350
£34.49
Fluval EVO/Spec Foam Filter
£5.35
Eheim Biopower 200 Internal Filter
£59.99
Sera Siporax Professional 500ml
£7.19
Hugo Kamishi Coarse Foam Filter Pad
£5.99
Tunze Osmolator Replacement Metering Pump
£23.19£25.90
Eheim Starter Bulb 9-25mm
£17.99
TMC V2Pure 100 Reverse Osmosis System
£118.99
Juwel Cirax XL
£14.95
TMC Reef-Fill Auto Top Up Replacement Pump (9848)
£19.99
Eheim Nozzle and Adaptor Pieces
£4.36
Tunze Osmolator 3
£199.90
Eheim Ehfikarbon - 2 ltr Freshwater Activated Carbon
£9.99
Eheim Ehfikarbon - 1 ltr Freshwater Activated Carbon
£5.99
EHEIM Experience 350 Coarse (Blue) Pads (x3)
£9.95
Alfagrog Filter Media E40 15L
£19.95
Fluval FX UVC In-Line Clarifier
£106.99£139.99
TMC v2 Auto Top Up Compact Standard Complete Unit (1 x Float Switch)
£54.99
ClariSea XL Fleece for SK3000 - 6 Pack
£84.39£89.94
UNS Dual AOI Filter Bag Conversion Kit
£9.95
Oase BioMaster 2 External Thermo Filter
£199.99£230.99
Sicce Shark PRO 700 Internal Filter
£56.99
Oase BioMaster Pre-Filter Foam 30ppi 6-Set 46482
£11.24
Have Questions About Freshwater Filtration?
We have answers. Get quick help for common questions.
What type of filter is best for a freshwater aquarium?
The best filter for your freshwater tank depends on its size, stock level, and setup style. External canister filters are ideal for medium to large tanks due to their strong flow and multi-stage filtration. Internal filters are great for small to mid-size aquariums and are easy to install. Sponge filters are perfect for breeding tanks or shrimp tanks, offering gentle biological filtration.
What are the different types of filtration in freshwater aquariums?
There are three main types of filtration: mechanical filtration removes physical debris like uneaten food and plant matter; biological filtration supports beneficial bacteria that break down toxic ammonia and nitrite; and chemical filtration uses media like activated carbon to remove odors, discoloration, and dissolved impurities.
How do I choose the right size filter for my tank?
Look for a filter rated for at least 3 to 5 times your tank’s volume per hour. For example, a 100-litre tank would need a filter with a minimum flow rate of 300 to 500 LPH. Overstocked or heavily planted tanks may benefit from more powerful filtration.
Are sponge filters enough for a freshwater tank?
Sponge filters are effective for smaller tanks, breeding setups, or tanks with delicate species like fry or shrimp. They offer gentle water flow and excellent biological filtration but may not be sufficient for heavily stocked or large tanks.
How often should I clean my freshwater aquarium filter?
In general, filters should be cleaned every 2 to 4 weeks, depending on the bio-load of your tank. Over-cleaning or using tap water can disrupt beneficial bacteria colonies, so it’s best to rinse filter media in old tank water to preserve biological filtration.
Do I need a filter in a planted or low-stock tank?
Yes. Even in planted or lightly stocked tanks, filtration is essential for maintaining water circulation, supporting bacterial colonies, and removing waste. However, flow strength may need to be reduced to avoid disturbing plants or slow-moving species.
Can I mix different types of filter media?
Absolutely. Many advanced aquarists customize their filtration by mixing sponge for mechanical filtration, ceramic rings or bio media for biological filtration, and carbon or resin for chemical filtration. This creates a more efficient and balanced filtration system.
What maintenance does a canister filter require?
Canister filters should be checked monthly and thoroughly cleaned every one to two months. This involves rinsing or replacing media, cleaning impellers, and ensuring all hoses and connections are free of clogs and debris.
Freshwater Aquarium Filters and Filtration
Good filtration is the most important part of any freshwater aquarium. A filter removes fish waste and debris, grows the beneficial bacteria that turn ammonia into less harmful nitrate, and keeps water clear and healthy. Choosing the right aquarium filter for your tank size and fish will make fishkeeping easier and help your fish live longer.
Our freshwater filtration range covers every type of filter. External filters from Eheim, Oase and Fluval sit in the cabinet and suit medium and large tanks. Internal filters are compact and easy to fit in smaller aquariums, while hang-on-back filters and sponge filters are ideal for nano tanks, shrimp and fry. We also stock filter tubing, spray bars, surface skimmers and spare parts.
Filter media is just as important as the filter itself. Use coarse and fine sponges for mechanical filtration, ceramic rings or Matrix for biological filtration, and carbon or phosphate removers when you need them. Our freshwater filter media range includes Seachem, Fluval and our own Charterhouse media. When starting a new tank, add nitrifying bacteria to help the filter mature faster.
Charterhouse Aquatics stocks freshwater filters from trusted brands with fast UK delivery. If you need help choosing between an internal and external filter, our team can recommend the right setup for your tank.
