going on vacation for a month, what should i do with my aquasana under sink filter?

Diagnosis

Leaving the Aquasana Claryum 3-Stage Max Flow system dormant for 30 days creates a condition known as water stagnation. Because the filter media (specifically the activated carbon and ion-exchange resins) is designed to be saturated, stagnant water trapped within the filter housings becomes a breeding ground for biofilm and opportunistic bacteria. When water sits motionless, the chlorine residuals typically found in municipal water dissipate, removing the primary chemical barrier against microbial growth. Furthermore, the internal pressure seals and O-rings can dry out or shift if the system is left under constant pressure without flow, potentially leading to slow leaks when you return. If you simply leave the system "on" but unused, the first few gallons you drink upon your return will contain concentrated contaminants and a "stale" metallic taste caused by the leaching of minerals from the filter housing walls into the stagnant water column.

How to Fix It

To ensure your system remains sanitary and the cartridges are preserved, follow this specific shutdown and restart sequence:

1. Locate the blue inlet shut-off valve on the cold water line leading into the Aquasana system. Turn the handle 90 degrees to the "Off" position to stop the flow of fresh water into the filter housings.
2. Open the kitchen faucet handle fully to the "Cold" position. Allow the water to run for 15-30 seconds. This relieves the internal pressure within the 3-stage cartridges and prevents pressure build-up from damaging the internal membranes while you are away.
3. Once the flow stops completely, close the faucet handle.
4. Upon your return, slowly turn the blue inlet valve back to the "On" position. Do not snap it open quickly, as a sudden pressure surge (water hammer) can cause the cartridges to jump in their housings.
5. Open the faucet and run the water at full blast for 3 to 5 minutes. You will likely see "cloudy" water or air bubbles; this is normal aeration. Continue flushing until the water is crystal clear and the flow rate returns to the Max Flow specification.
6. Taste the water. If a bitter or metallic taste persists after 5 minutes of flushing, run the water for an additional 2 minutes to fully purge the stagnant pockets in the second and third stages.

If That Didn't Work

• If you return and find the water flow is significantly restricted (reduced GPM), the filter media may have compacted during the stagnation period. Try loosening the filter housings by a quarter-turn and retightening them to reseat the cartridges.
• If the water has a strong "sulfur" or "rotten egg" smell after a month of inactivity, the carbon block has likely been compromised by bacterial growth. In this case, you must replace all three Claryum filter cartridges immediately, as flushing will not remove the biofilm from the internal pores of the media.
• If you notice a drip at the connection points after reopening the valve, check the 1/4" plastic tubing for kinks. Stagnant systems can sometimes develop "memory" in the tubing if they shift, requiring you to gently massage the tube or re-seat the push-fit connectors.
• If the water remains cloudy despite 10 minutes of flushing, check your home's main pressure regulator. A sudden spike in pressure upon returning can sometimes stir up sediment in the pipes that the Aquasana system then traps, requiring a full system flush.

Heads Up

• Never leave the system pressurized but unused for more than two weeks; the risk of biofilm accumulation in the final stage is too high.
• If your vacation coincides with a freeze warning, ensure the cabinet under the sink is insulated, as stagnant water in the filter housings can freeze and crack the plastic housings, leading to catastrophic flooding.
• Always check the date on your filter cartridges before leaving; if they are within 30 days of their expiration date, it is more efficient to replace them immediately upon your return rather than flushing old media.
• Avoid using chemical additives or "preservatives" inside the filter housings during your absence, as these can permanently ruin the ion-exchange resins in the Claryum stages.