A DI vessel is the simplest pure water setup there is: a pressure vessel filled with mixed bed resin, plumbed between the water supply and the pole. In a soft water area one vessel can be the whole system. In a hard water area the same vessel sits after an RO membrane and polishes the last few ppm out.

These are Spectrum SV-FK pressure vessels, supplied empty so you choose the resin. Both are 8 inches in diameter: the 11L stands 17 inches and holds 10.5 litres of resin, the 25L stands 35 inches and holds 23.6 litres. The shell is fibreglass over an HDPE liner, water contact parts are food grade, and the standard head carries 3/4 inch female ports with a 2.5 inch filling neck.

• Resin not included: fill with any mixed bed resin, such as FaceLift Resin, Unger Resin or Tulsion MB115.
• Fittings: the ports take a Hozelock male to 3/4 inch threaded connector, so the vessel plumbs into ordinary hose fittings.
• Mounting: the 8 inch DI Resin Vessel Holder clamps either size to a wall or tank.
• Refurbishing: a DI Vessel Distribution System is available for both sizes.

Rated to 10.5 bar, so mains pressure and pumped feeds are both well inside its limits. Filling is easier with the Blue Resin Funnel, and a TDS meter confirms the output is at 0 ppm before you start cleaning.

Mainland UK: shipped via DPD next day service.

• Free delivery: orders over £75 ex VAT qualify for free courier delivery.
• Smaller items: sent via Royal Mail Tracked 48, 3 to 5 working days.
• Oversized items: delivered by pallet within 2 to 4 working days; a signature is needed on delivery.
• Returns: free 30 day returns. The returns policy has the details, and you can start a return through the DPD returns portal.
• Same day dispatch available: orders placed before 3pm, Monday to Friday, are dispatched the same day at an additional cost. Select same day despatch at checkout.

Delivery times are not guaranteed, and Window Cleaning Warehouse cannot accept liability for items delivered to third party or unsecured addresses.