The Merlin does not list cysts among the controlled or reduced contaminants. Here is a link to a system that does control micro-organisms and many other contaminants:
PuROLine 5000 Reverse Osmosis Drinking Water System and PuROLine 5000 Replacement Filters Just about all of these systems can have the filters upgraded to reduce more contaminants. The replacement filters will be more expensive, but they will be higher quality also.
Reverse Osmosis water is extremely pure water. Most RO membranes filter water down to .0005 microns, which is incredibly small. It is highly unlikely that any microorganisms will get through. However, because it is possible for some contaminants to get through, NO water purification system can be 100% guaranteed to eliminate ALL contaminants. The Merlin is designed to be used with water that is potable, and is not designed for highly contaminated water with high quantities of micro-organisms. If you are using your Merlin for this kind of water, you will have exceptionally safe and pure water. Your neighbors will be knocking on your door with empty gallon jugs in their hands. If, however, you had hoped to use this system on water that is highly contaminated, then you will need a system that would be a lot more expensive.
Thank you,
WaterFilters.NET