Tetra EasyCrystal FilterPack C250/300 is a set of replacement filter cartridges with activated carbon for Tetra EasyCrystal Filter 250 and EasyCrystal FilterBox 300 internal filters. According to the description, the sponges provide mechanical, biological and chemical filtration. A two-sided sponge removes the finest dirt particles: the white side for pre-filtration, the green side for fine filtration. Special activated carbon tackles water pollution and odours. The cartridge design lets you change it without getting your hands dirty.
What the manufacturer claims
Tetra promises crystal-clear, healthy water and calls the cartridge innovative: it is removed and inserted as a whole, without taking the sponges apart. The same cartridge fits two filter models in the EasyCrystal range.
Key specifications
| Parameter | Value |
|---|---|
| Type | replacement cartridge for an internal filter |
| Compatibility | EasyCrystal Filter 250, EasyCrystal FilterBox 300 |
| Mechanical filtration | two-sided sponge: white and green side |
| Chemical filtration | activated carbon |
| Biological filtration | claimed |
| Quantity per pack | not in the description; the page address says 3 |
| Replacement interval | not stated in the listing |
| Barcode | 4004218151598 |
Pros
- Clean replacement. The whole cartridge is swapped and your hands stay dry.
- Two mechanical stages. Coarse and fine filtration in one sponge.
- Activated carbon. Removes odours and dissolved pollutants.
- Two filter models. Fits EasyCrystal 250 and 300.
- Genuine consumable. Fits exactly.
- Clear water. The cartridge's main purpose.
Cons and what to watch
- No quantity in the description. The pack count appears only in the page address.
- No replacement interval. It does not say when to change it.
- Carbon and medication. Carbon absorbs treatments, so it must be removed during them.
- Own range only. It will not fit other filters.
How the cartridge works
Water first passes through the white side of the sponge, which traps larger particles, then through the green side, which removes fine suspended matter. Activated carbon adsorbs dissolved organics, colourants and odours. Over time, beneficial bacteria settle on the sponge and process ammonia and nitrites — this is biological filtration.
When to replace it
The listing gives no replacement interval. Go by the sponge's condition and the flow: if water from the filter is noticeably weaker and rinsing does not help, it is time to change the cartridge. Activated carbon becomes saturated over time and stops working, so the cartridge should be fully replaced regularly even if the sponge looks fine.
How to keep the bacteria
When you replace the cartridge, part of the beneficial bacteria colony goes with the old sponge. To protect the tank, do not change the cartridge and most of the water on the same day, and do not clean the substrate and decor at the same time. Bacterial additives such as Tetra SafeStart or Tetra Bactozym can help restore the colony.
Rinsing between replacements
If the sponge clogs early, rinse it gently in aquarium water rather than under the tap: chlorinated water kills bacteria. Do not use soap or cleaning products.
Carbon and fish treatment
Activated carbon absorbs medication and many water treatments. During fish treatment or algae control, for example with Tetra Algetten, the carbon cartridge is usually removed, and a fresh one is fitted after the course to remove residues.
Alternatives
For other filters, universal media work: Resun 35 PPI sponge and JBL Symec filter floss, which can be cut to size.
Who it suits
The cartridges suit owners of Tetra EasyCrystal Filter 250 and FilterBox 300 who want a convenient consumable for clear, odour-free water. Other equipment is in fish equipment.
Verdict
Tetra EasyCrystal FilterPack C250/300 is a genuine replacement cartridge with a two-sided sponge and activated carbon that is easy to swap. The downsides are that the description gives no cartridge count or replacement interval, and the carbon has to be removed during fish treatment.
FAQ
Which filters does it fit?
Tetra EasyCrystal Filter 250 and EasyCrystal FilterBox 300.
How many cartridges are in a pack?
The description does not say; the page address says 3.
How often should it be changed?
No interval is given; change it when flow weakens and regularly because of the carbon.
Can it be rinsed?
Yes, in aquarium water, without soap.
Should it be removed during fish treatment?
Yes, the carbon absorbs medication.
Is there biological filtration?
Yes, beneficial bacteria settle on the sponge.
What do the white and green sides mean?
White is coarse filtration, green is fine.
