How to replace DI resin. Bring your tank back to 0 TDS.
To replace the DI resin in a Spot Free Rinse tank, flush the old resin out with water pressure, pour fresh mixed bed DI resin in through the filling funnel, reassemble the tank head and run water until your TDS meter reads 0 ppm. It takes about 15 minutes with no tools. Watch the video, then work through each step below.
What's in your kit and tank
Match the names used in the steps below to the parts shown here. Everything in the first card comes with our resin replacement kit (sometimes searched as a DI resin refill kit).
In your replacement kit
- 5 L vacuum-sealed DI resin bags (quantity depends on your order)
- Custom filling funnel with safety cap
- Cloth bag for catching old resin
- Centre extraction tube
- Small extraction hose
Tank components
- Tank head with "IN" and "OUT" connectors
- Top basket and bottom basket
- Riser tube (centre)
- Mesh seal (resin trap) inside the "OUT" fitting
- Rubber seal on the tank head
What you'll need
A few household basics. The kit covers the rest.
- Your Spot Free Rinse deionised water tank
- External tap with garden hose
- Masking tape (recommended not necessary)
- Scissors
- A space where spills are easy to clean up
Resin replacement instructions
Work through each step to empty, fill, reassemble, and test your tank.
Removing old resin
Flush and empty
- Attach hose to the "IN" connector and fill the tank until water exits the "OUT" connector. The tank needs to be full of water.
- Unscrew the lid slowly — water level should be near the top. Top up if needed. This makes removing the centre tube and filters easier.
- Lift out the lid, top basket, riser tube, and bottom basket together. If the centre tube stays in the tank, remove it separately.
- Insert the white extraction tube fully into the bottom of the tank head and screw the head back on.
- Connect a hose from your tap to the "IN" fitting in the tank head.
- Connect the small extraction hose into the "OUT" connector and place the other end into the cloth bag. Pull the drawstring tight around the hose.
- Turn the tap to full pressure. Resin will flush into the bag while water drains through.
- When the water runs clear, continue flushing for one more minute.
- Let the cloth bag drain completely. Bag and bin the old resin — never down sinks or drains.
- Tip any remaining water out of the tank.
Getting ready to add new resin
Prepare the tank
- Open a 5 L resin bag carefully with scissors. Avoid spilling the resin.
- Place the original riser tube with bottom basket back inside the tank.
- Place tape over the top of the tube to block any resin that might get in (recommended).
- Attach the filling funnel and make sure the safety cap blocks the riser tube opening.
Filling with fresh resin
Add new resin
- Pour the mixed bed resin slowly through the funnel in small amounts to avoid clumping.
- Tap or shake the tank and funnel gently to help the resin move through.
- Repeat for additional resin bags as required.
- Lightly compact by lifting the tank 10–15 cm and tapping the base on the ground. Don't use excessive force.
- Resin level should sit just below the bottom of the funnel. The more you can safely pack in, the longer it lasts.
- Bags sometimes contain slightly more resin than the tank holds, so you may have a small amount left over.
Reassembling the tank
Put it back together
- Remove the funnel.
- Wipe the tank threads with a cloth so there is no resin left in the threads.
- Remove the white extraction tube from the tank head.
- Guide the riser tube through the top basket and refit the tank head.
- Screw the tank head on firmly, making sure the rubber seal is seated correctly.
Testing your water
Verify 0 TDS
- Run water through the tank for around 10 seconds before testing.
- Check the outlet water with your TDS meter.
Tips & safety
A few extras to make resin last longer and keep things safe.
Helpful tips
Good practice
- Store any unused resin in a sealed bag in a cool, dry place.
- Shake the tank occasionally to maintain even resin distribution.
- Never pour resin down sinks or drains.
Safety notes
Extra safety
- Keep resin away from children and pets.
- Clean spills immediately — dry beads are extremely slippery on floors.
- Dispose of used resin bagged in normal household waste.
Resin replacement questions
The questions we get asked most about DI resin.
How often should DI resin be replaced?
It depends on how long the DI resin lasts in your water. Resin life is driven by your tap water's TDS and how much you rinse — on roughly 100 ppm water, a 10L tank delivers around 85–97 rinses before the resin is exhausted. Replace it when your output TDS climbs above 10 ppm or water spots start returning.
How do I know when the resin is exhausted?
Watch for TDS creep. Fresh resin reads 0 ppm on the included TDS meter; as it exhausts, the reading climbs to 5 ppm, then 10 ppm and beyond. Light spotting after a rinse is the visual giveaway — check the meter, and replace the resin once it passes 10 ppm.
Can I use any mixed bed resin in the tank?
The tank accepts standard mixed bed DI resin, but resins vary enormously. Ours was selected after testing more than 20 types to hold 0 ppm at full residential flow rates — many cheaper resins can't. For guaranteed spot-free results on your cars, caravans, boats, windows and solar panels, use a genuine resin replacement kit.
How do I store spare resin?
Keep unused resin vacuum-sealed or in an airtight bag, in a cool, dry spot out of direct sunlight. Heat and air exposure slowly degrade resin. Stored well, sealed resin keeps for years — ready for your next replacement.
