NSA 25i / 251 Replacement Water Filter


The discontinued NSA 25i / NSA 251 can be now replaced with the more advanced 4 stage GW3 inline under sink water filter from Glacier Water Systems.

Upgrading your water filter is hassle free! You can install your replacement water filter with the same connections as the old model NSA 21i / NSA 251 – check the connections before ordering.

This GW3 has just been updated. New model available now. Same connections. No photos just yet. New model will now be sent on all orders.

Click an option below to buy online.


Key Features of the *NEW*  GW3 Under Sink Water Filter

  • The discontinued NSA 25i NSA 251 Replacement Water Filter can now replaced with the more advanced Glacier GW3 water filter.
  • The new GW3 is a direct replacement for the NSA 25i NSA 251 Replacement Water Filter and has the same fittings as the NSA 25i and NSA 251.
  • This means the upgrading of your water filter will be straight forward and you should not require a plumber.
  • The GW3 inline water filter lasts up to 2 years completely maintenance free! 
  • This NSA replacement water filter has the ability to absorb more chemicals, chlorine and heavy metals.
  • Dimensions – 31cm x 7.5cm. Fits compactly underneath the kitchen sink.

Installing the GW3 water filter replacement for NSA 25i / NSA 251

  • The GW3 direct replacement water filter has the same fittings and is a straight replacement – check the connections before ordering.
  • Check to see how your current NSA water filter is installed – does the filtered water come through a separate tap on the side of the sink? If you would like to upgrade your whole drinking water system, please click on the appropriate drop down above.
  • Complete with DIY fitting instructions for a hassle free installation.

Dr Brian, Co Tipperary, testimonial for NSA water filter replacement.

Why a Glacier Replacement Water Filter?

Innovative – Glacier water filters are designed with Bacteriostatic Water Treatment technology, allowing our water filters to last between 2-3 years.

Natural – Granular Activated Carbon is used in 4 or 5 different stages within Glacier water filters to ensure the filtration process is as natural and organic as possible.

Simple – Supplied with the same  connections, the installation of this GW3 water filter replacement is easy and hassle free so you can enjoy drinking water free from chlorine, chemicals and heavy metals for up to another 2 years.




Our customers are our business




Cost effective 

Cost of your replacement filter £135
That is only £67.50 per year
£5.63 per month
£1.40 per week
Clean, fresh, filtered water for only £0.20 per day

For more technical information, please download the PDF Specification for the GW3 Water Filter or click on additional information tab.

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