In stock · ships freeClarisink Limescale Defender Under-Sink Filter
£119.00
VAT included · Free UK delivery · Typically arrives in 4–21 business days
- Tracked delivery on every order
- 60-Minute Simple DIY Setup
- 2-Year Comprehensive Warranty
- Engineered for Hard UK Tap Water
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- Free UK delivery on every order, no minimum spend
- 2-year warranty on all filtration systems
- 30-day returns if it isn't right for your kitchen
- Fits a standard UK cold feed — no plumber required
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Best under sink water filter UK families can rely on
Finding the best under sink water filter uk families can rely on is essential if you want to eliminate cloudiness, chemical odours, and heavy limescale from your daily kitchen tap water.
About this product
If you live in London, the South East or East Anglia, your water is hard, and the symptoms are familiar: a chalky ring in the kettle, cloudy glassware, and a boiler that costs a little more to run every year. The Limescale Defender targets that specific problem.
It works by sequestration. A polyphosphate cartridge holds calcium and magnesium in suspension so they stay dissolved instead of crystallising out onto heating elements and tap fittings. Alongside it, a carbon block deals with chlorine so the water tastes better as well.
Be clear about what this is and is not. It is not a water softener — the minerals are still in the water, they simply stop depositing. That is usually what people actually want, because softened water has its own drawbacks and a full softener is a considerably bigger installation.
For dissolved solids, fluoride or lead, this is the wrong product and reverse osmosis is the right one. For scale and taste in a hard-water postcode, it is the simpler and cheaper answer.
Tracked delivery in 4-21 business days depending on the item. That is slower than a next-day marketplace and we would rather say so up front than surprise you at the door.
Technical specifications
- Connection size
- Standard UK 15mm push-fit / compression
- Micron rating
- 5 micron
- Lifespan
- Cartridge replacement intervals vary by stage — follow the schedule in your user manual
Litres and centimetres are used throughout. Cartridge life is measured in litres of filtered water, so heavily used households will change theirs sooner.
What scale reduction does and does not do
A point-of-use scale filter treats the water drawn from one outlet, which is the water that ends up in your kettle, coffee machine and cooking pans. It is not a whole-house softener and will not change how your shower feels or how much detergent your washing machine needs. For most households that trade-off is the right one: the appliances that suffer most from scale are the ones fed by the kitchen tap, and treating only those keeps the cost and the installation work proportionate.
The chemistry differs from a salt-based softener too. Rather than exchanging calcium and magnesium for sodium, a scale-reduction media conditions the hardness minerals so they stay in suspension instead of crystallising onto hot surfaces. Nothing is added to the water, no drain connection is required, no electricity is used, and the mineral content that gives British tap water its character is retained. That makes it suitable for rented properties where notifiable plumbing work is not an option.
Expect the improvement to show up gradually. Existing scale inside a kettle will not disappear on its own — descale once after fitting, and from then on the deposit builds far more slowly. Glassware spotting and the film on the surface of tea usually improve within days, because those come from freshly drawn water rather than accumulated deposit.
Specifications
| Filtration stages | 2 (carbon block + polyphosphate scale inhibitor) |
|---|---|
| Filtration rating | 5 micron |
| Flow rate | approx. 3.8 litres per minute |
| Cartridge capacity | approx. 8,000 litres |
| Cartridge life | approx. 12 months |
| Housing size | Standard 10-inch |
| Power required | No |
| Waste water | None |
| Under-sink footprint | approx. 13cm W x 35cm H x 13cm D |
Figures marked with this symbol are provisional and are being confirmed against the manufacturer's datasheet. We publish them as estimates rather than leaving the row blank, and we do not claim any certification or test result we cannot evidence.
What this filter addresses
- Scale-forming behaviour of calcium and magnesium (sequestered, not removed)
- Chlorine and chlorine taste
- Sediment and particulates
What it will not do
- This is scale inhibition, not softening. The polyphosphate stops calcium and magnesium from crystallising and sticking to surfaces — it does not take them out of the water. A hardness test will read the same before and after.
- It does not reduce dissolved solids, fluoride or nitrates. If that is your goal, you need reverse osmosis.
- It protects the appliances downstream of the filter only. A whole-house scale problem needs a mains-position unit.
- Polyphosphate is depleted by use rather than by time, so heavy-use households will need the cartridge sooner than 12 months.
Will this fit?
Check these before you order — they are the questions we are asked most often.
- Standard 10-inch cartridge housing
- Takes replacement cartridge CS-LSC1
- Pairs with the CS-TAP3C 3-way tap, or use your existing tap with a separate filter faucet
Still not sure? Send us your sink and pipework details and we will confirm before you buy.
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