received by the International Bureau on 03 April 2014 (03.04.2014)

1. A method, comprising:

inserting a filter media component containing a type and an amount of activated carbon within a fluid pumping system for an aquatic reservoir in which maintenance of a minimum level of chlorine is desired, the amount of activated carbon sufficient for the type of activated carbon to produce a desired reduction in cyanuric acid concentration in fluid within the reservoir within a predetermined period,- pumping the fluid from the aquatic reservoir through the activated carbon in the filter media component for the predetermined period to reduce an amount of cyanuric acid within the fluid to the desired cyanuric acid concentration;

removing the filter media component containing the activated carbon once a remaining cyanuric acid concentration within the fluid falls below a desired concentration; and

adding chlorine to the fluid to restore a level of chlorine in the fluid to at least the minimum level of chlorine desired. 2. The method according to Claim 1, further comprising: placing the filter media component on top of loose filter media within a filter housing, between a diffuser and a lateral outlet assembly, the filter media component spanning a region between a supply line to the diffuser and interior surfaces of the filter housing.

3. The method according to Claim 1, further comprising: connecting the activated carbon filter media component to a manifold sized to receive a diatomaceous earth filter media component, the activated carbon filter media spanning an outlet from a filter housing.

4. The method according to Claim 1, further comprising: mounting an annulus formed by porous materials and filled with the activated carbon within a filter housing in a position spanning a fluid communication path between an inlet and an outlet for the filter housing at at least one point along the fluid communication path.

5. The method according to Claim 1, further comprising: replacing the activated carbon filter media component with a traditional filter media component.

6. The method according to Claim 1, further comprising: reducing both a level of chlorine in the fluid and a level of cyanuric acid within the fluid.

7. A system, comprising:

a filter receptacle for a filter configured to filter water from an aquatic reservoir in which maintenance of a minimum level of chlorine is desired, the filter receptacle having an inlet configured to admit fluid into an interior space of the filter receptacle and an outlet configured to permit passage of fluid from the interior space; and

a filter media component sized to fit within the filter receptacle and configured to span a fluid communication path within the interior space between the inlet and the outlet at at least one point. along the fluid communication path, the filter media component containing coconut shell activated carbon in a quantity sufficient to reduce levels of cyanuric acid within water from the aquatic reservoir. 28

8. The system according to Claim 7, wherein the filter media component is configured to rest On top of loose filter media within the filter receptacle, between a diffuser and a lateral outlet assembly, and to span a region between a supply line to the diffuser and interior surfaces of the filter housing.

9. The system according to Claim 7, wherein the coconut shell activated carbon filter media component is configured to connect to a manifold sized to receive diatomaceous earth filter media component, and to span an outlet from the filter receptacle .

10. The system according to Claim 7, wherein the filter media further comprises:

an annulus formed by porous materials and filled with the coconut shell activated carbon, the annulus configured to pass fluid from the inlet through a sidewall of the annulus and to pass fluid from a center conduit of the annulus to the outlet. 11. The system according to Claim 7, wherein the filter media further comprises:

an enclosure formed of a porous material and configured to contain the coconut shell activated carbon in a body sized to span the fluid communication path between the inlet and the outlet at the at least one point.

12. The system according to Claim 7, wherein the filter media further comprises :

a rigid enclosure with openings and covered by a porous material, the rigid enclosure and the porous material collectively configured to contain the coconut shell activated carbon in a body sized to span the fluid communication path between the inlet and the outlet at the at least one point. 29

13. A filter media component, comprising:

a porous material forming an enclosure sized to fit within a filter receptacle and configured to span a fluid communication path within an interior space of a filter receptacle for a filter configured to filter water from an aquatic reservoir in which maintenance of a minimum level of chlorine is desired, the interior space in fluid communication with an inlet configured to admit fluid into the filter receptacle and an outlet configured to permit passage of fluid from the interior space; and

a body of coconut shell activated carbon within the enclosure in a quantity sufficient to reduce levels of cyanuric acid within water from the aquatic reservoir. 14. The filter media component according to Claim 13, wherein the filter media component is configured to rest on top of loose filter media within the filter receptacle, between a diffuser and a lateral outlet assembly, and to span a region between a supply line to the diffuser and interior surfaces of the filter receptacle.

15. The filter media component according to Claim 13, wherein the coconut shell activated carbon filter media component is configured to connect to a manifold sized to receive diatomaceous earth filter media component, and to span an outlet from the filter receptacle.

16. The filter media component according to Claim 13, wherein the filter media further comprises:

an annulus formed by porous materials and filled with the coconut shell activated carbon, the annulus configured to pass fluid from the inlet through a sidewall of the annulus and to pass fluid from a center conduit of the annulus to the outlet. 30

17. The filter media component according to Claim 13, wherein the filter media further comprises:

an enclosure formed of a porous material and configured to contain the coconut shell activated carbon in a body sized to span the fluid communication path between the inlet and the outlet at the at least one point.

18. The filter media component according to Claim 13, wherein the filter media further comprises:

a rigid enclosure with openings and covered by a porous material, the rigid enclosure and the porous material collectively configured to contain the coconut shell activated carbon in a body sized to span the fluid communication path between the inlet and the outlet at the at least one point.

19. The method according to Claim 1, wherein the type of the activated carbon is coconut shell activated carbon. 20. The system according to Claim 7, wherein an amount of the coconut shell activated carbon within the filter media component is sufficient to produce a desired reduction in cyanuric acid concentration in water within the aquatic reservoir within a predetermined period.