Under-sink water filter – which one to choose? | CzystyStyl Guide
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🧩 What types of under-sink filters are there?
There are mainly two types of filters used under the sink, which differ significantly in effectiveness and purpose.
1. Sorption filters (carbon)
These are the simplest and cheapest systems.
They use activated carbon cartridges and mechanical filtration.
They remove:
- chlorine,
- unpleasant smell and taste,
- basic mechanical impurities.
They do not remove:
- bacteria and viruses,
- heavy metals,
- microplastic,
- drug and pesticide residues.
👉 Good for municipal water if you only want to improve taste and odor. Sorption filters do not soften water.
2. Reverse Osmosis (RO) Filters
These are the most effective systems available on the market.
They filter water through a membrane with a permeability of up to 0.0001 microns ,
thanks to which they remove up to 99.8% of pollutants .
They remove, among others:
- heavy metals (lead, copper),
- bacteria and viruses,
- microplastic,
- chemical compounds,
- limescale and water hardness.
This is the best choice if you want clean, healthy and perfect drinking water straight from the tap .
🚰 RO filters with and without a tank – what is the difference?
It is worth emphasizing that tankless filters (Direct Flow) are also reverse osmosis filters .
This is not a separate type of filter – it is a modern version of the RO system , differing in design.
⭐ RO filters with tank (older generation)
- the water first goes into a plastic tank,
- slower filtration,
- they take up a lot of space,
- Water can stay in the tank for many hours.
⭐ Tankless RO filters (Direct Flow – new generation)
- real-time filtering , no storage,
- always fresh water ,
- high efficiency (300–600 GPD) ,
- saving space under the sink,
- fewer components to fail.
Examples of such filters:
👉 Tankless filters are currently the best choice for the kitchen – they combine the highest water quality with convenience and small size.
🧠 What to pay attention to when choosing an under-sink filter?
1. Membrane quality and number of filtration stages
Good models have 4-5 stages and a high-efficiency membrane.
2. Performance (GPD)
The higher the value, the faster you will fill the glass.
300–600 GPD is a good standard in 2025.
3. Availability of cartridges and operating costs
Philips, Ecosoft, Midea, Vio, Aquaphor filters have widely available, inexpensive cartridges.
4. Easy installation and service
Newer models have quick connectors, click-on replacement, and built-in sensors.
5. Additional features
- mineralization,
- intelligent filter replacement reminders,
- leak protection,
- automatic membrane rinsing.
