What is DI Resin?

Q: "What is DI Resin?"
Q: "What is DI Resin used for?"

• Deionisation (DI) resins are water filters that look similar to sand, being made from lots of tiny beads. They are used for removing impurities from water as it percolates its way through. In doing this they also chemically change the water. It’s an ion exchange process and some ions go from the water into the resin while others go from the resin into the water. This makes the water particles almost like little magnets that attract the dust and dirt particles from the surface of the glass. Sounds complex? It is! But thankfully for window cleaning uses we just need to know that deionised water will clean the windows perfectly and even though we leave the windows wet they will dry spotless.

Q: "What does TDS mean?"

• 'Total Dissolved Solids'. In water this means the amount of minerals and other things dissolved in the water. For perfect results in window cleaning we need 000 TDS.

Q: "What does PPM mean?"

• PPM stands for 'Parts Per Million'. In window cleaning terms we use this to describe how pure water is. So if you took exactly 1 million particles (molecules) of water and counted out how many of them are NOT water molecules, you would be counting PPM. For window cleaning it's generally accepted that we need a maximum of 10PPM to get good results on the glass.
• In reality, rather than trying to count microscopic particles, we use a small tool called a TDS Meter to measure the water purity by an electrical process. This is able to tell us the PPM of the water, or the TDS (see above). Once you have one of these meters and start using it in various locations you’ll be amazed how much variation there is in water quality from place to place.

Q: "What does 'Mixed Bed' mean?"

• DI Resins are made from two different kinds of elements: Cations and Anions. These are mixed together to make a single resin.

Q: "What is 'Virgin' resin?"

• It's possible to take old and exhausted resin and regenerate it for use again. This is an expensive process and the end result is an inferior resin that will fail sooner and often less predicatably. For this reason all the resins we sell are of the highest quality and fresh.

Q: "What size resin vessel should I use?"

• The actual size of the resin vessel or container is not important for the purity of the water. The resin will perform the same in whatever quantity it is used, so 1ltr of resin will filter the same amount of TDS out of the water if it’s 1ltr on its own or part of a larger quantity of resin. All it has to do is make the water 0PPM and it should do this as soon as the water touches it. Make sense? So 10ltr of resin will filter 10 times more TDS out of the water than 1ltr of resin will. But it will not make the water more pure than 0PPM. The larger vessel just means you can filter more water before the resin inside it will become exhausted and need changing. If using a small quantity of resin it's more important to check the readings very often in order to notice the changes before it's too late.

Q: "How much time does it take to filter the water?"
Q: "Will my water lose pressure inside the resin vessel?"

• Resin does not slow down the water flow very much at all, so for normal flow rates the resin will not make any noticable difference to the speed of the water, or the pressure. If you find the water pressure is low after the resin vessel it's probably due to air in the vessel. If this is the case just unscrew the vessel a tiny bit, to allow the air to escape.

Q: "Could I use two resin vessels, one after the other, to get better economy?"

• Actually yes, though it's more work for you. Initially the first vessel will do all the purification of the water and the next vessel will do nothing, but as the resin in the first vessel becomes exhausted the water will pass straight through unfiltered and the second vessel will start to do the filtering. Once the resin in this second vessel is also exhausted you have to change the resin in the first vessel and swap their positions. This puts fresh resin in the second vessel and keeps the water coming out pure. Keeping this process going will save resin overall by maximising how much filtration the resin is able to do.

Q: "How should I store my resin?"

• Use it within its shelf life. Resin has a shelf life before it goes into the water, usually about a year from the date of manufacture. Once under water (in a vessel) the resin should last beyond this time period.
• Keep it moist. Once opened a bag has to be closed again immediately to keep the resin fresh and moist. This is where the re-sealable plastic tubs come in handy.
• Don't let it freeze! Resin can be damaged by frost. This can happen over the winter if the resin is stored outdoors, or in an unheated shed or unit. Usually, freezing the resin ruins its properties.

Q: "My resin started badly and got really bad very quickly. Is it faulty?"

• If the readings were very bad from the beginning and they quickly got worse after only a few litres of water had passed through, it probably was actually water softener resin, not DI resin. This is also an ion exchange resin and can easily be confused. This is quite a common mistake and the reason we have such different colours between our softener resin bags and DI resin bags - to try and make the difference more noticeable.
• Be sure to order DI resin for window cleaning water polishing, not softening resin.

Q: "Is there a maximum speed for my water to go through my resin vessel?"

• In general, the slower the water passes through the resin, the more time it has to circulate in the resin and this can give better results over time. The water flow rate we use in window cleaning is slow enough to give good performance.

Q: "Is it ok if my vessel freezes?"

• No! It could damage the vessel itself and the ice can also damage the resin.

Q: "I heard that I should shake my resin bottle sometimes. Is it true?"

• In theory yes! This can move the resin a little and reduces channelling (where the water cuts a passage through the resin and then just goes through that instead of circulating through the resin). However, if it’s mounted in a vehicle the motion of driving is enough to do the shaking. If it’s a static DI vessel then giving it a bit of a shake or wobble can help at times.

Q: "Should I empty the water from my resin vessel after I’ve used it?"

• No, you don't need to do this. The resin can be stored inside the vessel when the water is in there. Once under water the resin will last for a long time so the shelf life of the resin doesn’t apply any more. Emptying the water out will allow the resin to start to dry out and this is bad for it. Just make sure the resin can’t freeze.