Description
Meet the Darlly Spa/Pool Replacement Filter Cartridge [10100] (C-9999) — a 100 sq ft filtration workhorse engineered to elevate spa and pool water clarity. Built to fit a range of filter housings, this open-top, open-bottom cartridge is designed to deliver steady flow, thorough filtration, and easy maintenance, so you can enjoy pristine water with less hassle.
Why this cartridge stands out
- Generous 100 sq ft filtration area for extended run times between cleanings and improved contaminant capture, helping you maintain sparkling water with less frequent cartridge changes.
- Open top and open bottom design promotes higher flow and easier backwashing, reducing pressure drop and boosting overall system efficiency.
- Precise dimensions for universal compatibility: 10-1/6" diameter, 19-5/8" length, with a 3/8" top opening and a 6" bottom opening. This combination makes it a reliable drop-in replacement for many spa and pool filter models.
- C-9999 model versatility and Airwick, Heldor, Vak-Pak, Dyna-Pure compatibility mean fewer mismatches and more confident shopping for your existing setup.
- Opal bottom style combined with an open top design delivers efficient dirt interception while maintaining strong flow across the cartridge surface.
Perfect for a range of users and setups
Whether you’re maintaining a backyard spa, a hot tub, or a small-to-medium pool, this cartridge is built to handle the demands of regular use. It’s especially well-suited for systems that rely on standard 10-1/6" diameter housings and require a reliable, long-lasting replacement that won’t clog quickly under typical spa and pool debris.
Practical use cases and tips
- Routine replacement schedule: plan to replace every 6–12 weeks during peak use, or sooner if you notice decreased flow or water clarity.
- Backwash-aware maintenance: when backwashing, keep an eye on flow resistance; a noticeable drop often indicates it’s time for a new cartridge.
- Prolong cartridge life: rinse off loose debris after each use and store spare cartridges in a dry, cool place to preserve filter integrity.
- Water clarity goals: pair with proper sanitizer levels and regular skimming to maximize the cartridge’s effectiveness in capturing oils, dirt, and organic contaminants.
What’s included and compatibility notes
The Darlly 10100 is a dedicated replacement cartridge designed to fit a variety of spa and pool filtration systems. It’s listed as compatible with brands and configurations such as Airwick, Heldor, Vak-Pak, and Dyna-Pure, with an Opal bottom style and an open-top/bottom construction that supports efficient filtration and easy handling during maintenance. Always verify your current filter housing’s dimensions match the 10-1/6" diameter and 19-5/8" length to ensure a seamless fit.
Durable, dependable filtration you can trust
Invest in a replacement that’s built to perform under regular spa and pool use. The Darlly Spa/Pool Replacement Filter Cartridge [10100] delivers robust filtration capacity, convenient maintenance, and broad compatibility, so you can keep water inviting and ready for relaxation—without the guesswork.
| Application | Airwick, Heldor, Vak-Pak, Dyna-Pure |
| Bottom Style | Open |
| Model | Opal |
| Square Footage | 100 sq ft |
| Top Style | Open |
| Diameter | 10-1/6" |
| Length | 19-5/8" |
| Top | 3/8” Open |
| Bottom | 6” Open |


