4.9 out of 5 (500+ store reviews)
Perfect fit for my RO system. The size was exactly what I needed, delivery was fast and installation was as easy as push and go.— Mark T., verified buyer store review
MPN
£5.99 inc. VAT
*Applies when Next Day Delivery is selected at checkout.
Order before the delivery cut-off for the fastest available dispatch. Delivery options and final prices are confirmed at checkout.
Our size guide and fitting advice help you choose the right connection first time.
View Size GuideNot sure which fitting you need? Our experts are here to help you choose the right size and fitting for your system.
Learn moreThe BRITA Temporary Hardness Testing Kit provides an accurate reading of temporary water hardness (TDS), perfect for setting up the correct bypass on BRITA Purity filtration systems.
Use a BRITA drop test kit. Check that the test kit is still in date – see side of box (an out of date kit may give an incorrect reading).
The result will determine the bypass setting required on the filter head at installation.
Steps:
Example : One drop = 1 dH Carbonate Hardness, 10 drops = 10 dH Carbonate Hardness
Follow the manufacturer’s installation guidance and check all connections before leaving the installation.
Order before our dispatch cut-off — 3pm Monday to Friday, or 12pm on Saturday — and your order is sent the same day; anything after that follows the next working day. We don’t dispatch on Sundays, and you’ll get a tracking link by email as soon as your order is on its way.
Choose your UK delivery option at checkout:
We also ship internationally, with rates calculated at checkout.
Returns & refunds
Changed your mind? You have 30 days to return any unused filter in its original sealed packaging for a refund, or 90 days for exchanges. Start at our returns portal and either generate a prepaid Royal Mail label (£3.49, deducted from your refund) or use your own courier — exchanges are always free to return. We approve refunds within 24 hours of your return reaching us; your bank may then take 3–5 working days to show the funds.
The BRITA Temporary Hardness Testing Kit provides an accurate reading of temporary water hardness (TDS), perfect for setting up the correct bypass on BRITA Purity filtration systems.
Use a BRITA drop test kit. Check that the test kit is still in date – see side of box (an out of date kit may give an incorrect reading).
The result will determine the bypass setting required on the filter head at installation.
Steps:
Example : One drop = 1 dH Carbonate Hardness, 10 drops = 10 dH Carbonate Hardness
Follow the manufacturer’s installation guidance and check all connections before leaving the installation.
Order before our dispatch cut-off — 3pm Monday to Friday, or 12pm on Saturday — and your order is sent the same day; anything after that follows the next working day. We don’t dispatch on Sundays, and you’ll get a tracking link by email as soon as your order is on its way.
Choose your UK delivery option at checkout:
We also ship internationally, with rates calculated at checkout.
Returns & refunds
Changed your mind? You have 30 days to return any unused filter in its original sealed packaging for a refund, or 90 days for exchanges. Start at our returns portal and either generate a prepaid Royal Mail label (£3.49, deducted from your refund) or use your own courier — exchanges are always free to return. We approve refunds within 24 hours of your return reaching us; your bank may then take 3–5 working days to show the funds.