Aquasana OptimH2O replacement filters are sold at aquasana.com and Amazon (Aquasana storefront). The most important sourcing note: the integrated Claryum membrane module is an Aquasana-proprietary design -- there are no third-party substitutes that maintain NSF 401 certification. Using a non-Aquasana membrane in the OptimH2O may maintain some RO function but voids the NSF 401 certification and likely the NSF 42 and 58 certifications as well, because the Claryum medium is what delivers the 401-certified performance.
OptimH2O filter replacement schedule
| Filter | Aquasana part | Interval | Cost |
|---|---|---|---|
| Pre-filter set (stages 1-3, sediment + dual carbon) | AQ-RO3-PRE or OPT-PRE-KIT | 12 months | $45-$60 |
| Integrated Claryum RO membrane module | AQ-RO3-CLARYUM or OPT-MEM-CLR | 24 months | $60-$80 |
| Post-filter (if separate from Claryum module) | AQ-RO3-POST | 12 months | $20-$30 |
Annual cost estimate: $100-$140 (pre-filter + post-filter annually; Claryum membrane amortized ~$35/yr over 24-month life)
Annual maintenance kit
Aquasana sells the OptimH2O Annual Maintenance Kit (part OPT-AMK or similar) that includes the pre-filter set, post-filter, and one Claryum membrane. Buying the kit saves $15-$25 versus individual purchases and ensures all stages are refreshed on the same cycle. The membrane in the kit is a 24-month item -- the annual kit effectively provides one membrane every two years if you buy it annually and bank the second-year membrane.
How to replace OptimH2O filters
- Shut off the cold supply valve. Open the dedicated faucet to relieve pressure -- run until flow stops.
- Pre-filter housings (stages 1-3): unscrew counterclockwise with the filter housing wrench. Remove spent cartridges, rinse housings, inspect O-rings, apply silicone grease to O-rings, insert new cartridges, hand-tighten plus quarter-turn snug.
- Claryum membrane module: unscrew the membrane housing end cap. Pull the integrated module out carefully -- it is the combined RO membrane + Claryum medium unit. Insert the new module with the feed end entering first. Replace end cap firmly.
- Post-filter (if applicable): same housing wrench procedure as pre-filters.
- Restore supply pressure. Check all connections for drips. Flush the system for 2 minutes before resuming use.
Storage tank maintenance
The 3.5-gallon storage tank requires annual bladder pressure check. Shut off supply, drain the tank completely via the dedicated faucet, then check Schrader valve pressure -- should read 6-8 PSI with tank empty. Below 5 PSI: add air with a bicycle pump or low-pressure air compressor until pressure reaches 7 PSI. Over-pressurizing above 10 PSI compresses the bladder and reduces effective storage volume. If the tank cannot hold pressure (drops to 0 PSI within hours of charging), the bladder is failed and the tank needs replacement (Aquasana sells replacement tanks at $40-$60).
Where to buy genuine Aquasana filters
- aquasana.com: Direct from Aquasana; filter subscription available at 15% discount
- Amazon -- Aquasana store: Prime eligible, Aquasana-fulfilled
- Home Depot online: Aquasana filters are stocked for online order (limited in-store selection)
- Important: The Claryum membrane module must be purchased from Aquasana or an authorized retailer -- third-party "compatible" modules do not carry NSF 401 certification and defeat the purpose of choosing the OptimH2O