Reverse Osmosis (RO)

Q: "What does a Reverse Osmosis System do?"
Q: "Do I need a Reverse Osmosis System?"

• In order to improve the lifespan of the DI resin water can be filtered before it passes through. This is helpful as DI resin is the most expensive consumable in our systems. But even the best RO system can never fully filter the water, it will still leave some impurities in the water for the DI resin to remove. If the water in your area is already very close to pure then RO might not do very much to the water. It might be better to just use DI resin on it's own. In the majority of locations around the UK RO is the only economical way to produce enough water for window cleaning.

Q: "What is the pH of RO water?"

• Between pH5 and pH6, which makes it between 10 and 100 times more acidic than tap water. Which isn't much of a problem for most things as it's still a very mild acid.

Q: "What requirements do I need for my RO to run well?"

• There are 3 basic things:
  1. Good water pressure (Ideally at least 40psi / 2.8bar)
  2. Good water temperature (Household water temperatures are good enough although you will notice your system running slowly in the colder months when water temperatures drop)
  3. Good water flow rate (The exact amount varies according to the RO system)
  
  With these things right for the RO it will run well if it has been put together and is maintained well. Of course there can be specific problems and they are sometimes very confusing.

Q: "Will my Reverse Osmosis system be damaged by the cold?"

• When water freezes it expands and this can create problems with splitting housings or crushing the filters inside them.
• Freezing water will usually cause permanent damage to RO membranes. So filter systems should never be allowed to freeze.

Q: "My system doesn't filter like it used to before I changed the filters"

• Membranes are precision components and small variations can make a big difference to how they perform. So like anything, it shouldn't be a surprise if a new membrane will not work quite like the old one did. Sometimes new membranes work better than the old ones, sometimes a little worse, although they should still work within manufacturer's tolerances.  At the end of the day they will get the job done and keep you earning. 

Q: "I changed the pre-filters and there are still marks on windows after cleaning"
Q: "I changed the membranes and now there are marks on windows after cleaning"

• The filters in any RO machine are only for removing the majority of the impurities from the water. But any poor water quality after the whole RO filtration process is down to the DI resin. This is the last filter to process the water and the only one to deionise it. The reverse osmosis system is only there to help the DI resin to last longer.
• For more information on DI resin click here
• Don't forget if you store water after you filtered it there's a possibility contamination is getting in.

Q: "Why does my system waste so much water?"

• All RO filters will waste a lot of water. Most systems will waste about 60% of the water coming into them. This is healthy and normal performance.

Q: "What are the water readings my system should make?"

• This will depend on several variables including the water coming into the system, and those mentioned above. In good conditions they should usually remove between 75% and 95% of the impurities from the water.