Imagine diving into your pool on a hot summer day only to find cloudy water and tiny particles floating everywhere. You rely on your Dolphin robotic cleaner to handle the dirty work, but even the best robot struggles if its filter isn’t up to the task. That’s where Dolphin ultra fine filters come in. These specialized replacements capture microscopic debris like silt, sand, and fine organic matter that standard filters miss. Whether you own a Nautilus CC Plus, an S50, or an M400, upgrading to an ultra fine filter can transform your pool’s clarity. In this guide, we review seven top-rated options from brands like ULTICOR, SUNRRA, and Kerneed, and share what to look for when choosing the perfect replacement. If you’re dealing with persistent fine debris, also check out our guide on the best robotic pool cleaner filter for silt for more targeted advice.
Pros
- High-efficiency microfiltration captures fine dirt, sand, and leaves for pristine pool water.
- Works with a wide range of popular Dolphin robot models, reducing the need for multiple filter types.
- Easy to clean and maintain with no special tools required.
- Affordable price compared to manufacturer replacement filters.
- Solid build quality with lightweight yet sturdy plastic construction.
Cons
- Not compatible with Dolphin Nautilus CC Pro or CC Supreme models, limiting its use for newer variants.
- Older versions of Active 10 or S50 may require removal of a plastic piece for proper fit, which could be inconvenient for some users.
- As an aftermarket part, it may not perfectly match OEM quality or warranty coverage.
The Ulticor Ultra Fine Filter Basket is an aftermarket replacement designed specifically for a wide array of Dolphin robotic pool cleaners. It is an ideal choice for pool owners who already own compatible models such as the Dolphin S50, S100, Active 10/15, Echo, T15, T25, Proteus DX3, Saturn, Cayman, Escape, and others. This basket is not intended for the Nautilus CC Pro or Supreme versions, so buyers should verify compatibility before purchasing.
What sets this filter apart is its microfiltration technology, which captures even the tiniest debris particles. In real-world use, this translates to a noticeably cleaner pool with clearer water, as fine dirt, sand, and pollen are effectively trapped. The basket is easy to rinse and clean every four to six weeks, maintaining peak performance without hassle. Users report that it fits snugly and works reliably cycle after cycle.
The design is straightforward: a white, lightweight plastic basket measuring roughly 9x5x7 inches. Build quality feels solid for an aftermarket part, though it may not have the exact finish of an OEM component. The inclusion of installation tips for older Active 10 or S50 units (which may need a small internal plastic piece removed) shows attention to compatibility details. A video guide is available upon request to assist with that adjustment.
Potential drawbacks are mostly centered on fitment limitations. Owners of Nautilus CC Pro or Supreme will need to look elsewhere. Also, the need to modify older robots could be a minor inconvenience for those not comfortable with simple DIY tasks. However, for the vast majority of compatible users, installation is plug-and-play.
Overall, the Ulticor Ultra Fine Filter Basket offers excellent value for money. It delivers superior filtration at a lower price than official replacements, while covering a wide range of popular Dolphin models. If you own one of the listed robots and want to keep your pool sparkling clean without breaking the bank, this filter is a smart buy.
Pros
- Microfiltration prevents clogging and maintains strong suction for thorough cleaning
- Sturdy ABS construction ensures durability even in heavy-duty use
- Wide compatibility saves hassle of finding exact match for various Dolphin models
- Simple maintenance with periodic rinsing; no tools required
- Cost-effective alternative to OEM parts with comparable performance
Cons
- May require more frequent rinsing if the pool is heavily soiled or has fine debris
- Only one basket included; some pool owners may need to purchase additional for larger pools
- Not compatible with all Dolphin models; verify compatibility list before purchase
The Fiitzn Ultra Fine Filtration Basket is a replacement filter designed for a wide range of Dolphin robotic pool cleaners, including models like the S50, Active 15, Echo, Nautilus CC, Encore, E10, E20, Proteus DX3, Solo, and Advantage. This part (9991460-R1) is ideal for pool owners seeking an affordable, high-performance alternative to the original filter. It is especially suited for those who want to improve water clarity by trapping fine particles without sacrificing cleaning efficiency.
The standout feature of this basket is its microfiltration technology, which captures small debris while allowing larger particles to pass through. This design prevents the filter from clogging quickly, ensuring consistent suction and longer cleaning cycles. In real-world use, this means less downtime for rinsing and more effective pool maintenance, even in dirty conditions. The basket maintains strong performance over weeks of use before needing a quick rinse.
Build quality is solid thanks to the ABS plastic frame, which resists cracking and deformation under pressure. The filter layer is securely supported, reducing the risk of tearing during operation. Installation is straightforward: it fits exactly like the original part, so no modifications or adapters are needed. Rinsing every 4-6 weeks keeps it working optimally, and with proper care, the basket can last 2-3 years, offering excellent value.
One potential drawback is that in extremely dirty pools, the filter may need more frequent rinsing to maintain flow. Additionally, the package includes only one basket, so owners of larger pools might need to buy a second. Also, while compatibility is broad, it does not cover every Dolphin model, so double-checking the list is wise. These are minor trade-offs for the price and performance.
Overall, the Fiitzn Ultra Fine Filtration Basket delivers on its promise of efficient fine debris capture and durability. It is a smart upgrade or replacement for Dolphin pool cleaner owners who want to keep their water crystal clear without breaking the bank. The combination of microfiltration, sturdy construction, and broad compatibility makes it a reliable choice for routine pool care.
Dimensions: 9.1 x 7.1 x 5.3 inches
Weight: 1 pound
Material: ABS plastic frame with microfiltration mesh
Compatibility: Dolphin models S50, S100, Active 15, Echo, T15, Proteus DX3, E20, Cayman, Escape, Nautilus CC, Encore, E10, Solo, Advantage
Replaces OEM Part: Maytronics 9991460-R1
Maintenance: Rinse every 4-6 weeks; expected lifespan 2-3 years with proper care
Pros
- Superior filtration from ultra fine pleated material, outperforming standard non-pleated filters.
- Durable ABS frame withstands regular use and chemical exposure without cracking.
- Cost-effective 4-pack reduces per-cartridge cost and frequency of replacement.
- Easy to clean and reuse, extending the life of each filter panel.
- Backed by a 1-year warranty for added confidence.
Cons
- Not compatible with older Nautilus CC, Nautilus (original), or Triton models; verify your robot before ordering.
- Some users may find the initial fit slightly snug in certain robot models, though it settles over time.
- Pleated filters may require more frequent rinsing in heavy-debris pools compared to coarse mesh options.
The SUNRRA Ultra Fine Filters are a versatile replacement option for a wide range of Dolphin robotic pool cleaners, including the Nautilus CC Plus, CC Supreme, M200, M400, M500, and many others. If you own one of these popular Maytronics models and want to improve water clarity, this 4-pack of pleated cartridges is a smart upgrade.
What sets these filters apart is their ultra fine pleated construction. Unlike standard non-pleated cartridges that let fine sediment slip through, the dense pleats trap even tiny particles like algae, pollen, and dust. The result is noticeably clearer pool water and a cleaner floor after each cycle. In real-world use, the filtration performance is excellent, especially for pools that struggle with cloudy water.
The build quality is solid: the frame is made from heavy-duty ABS plastic that resists cracking and tearing, even after repeated rinsing and seasonal storage. SUNRRA claims a lifespan of 2-3 years, which is reasonable if you clean them every 4-6 weeks. The 4-pack also means you have spares on hand, saving you from last-minute replacements.
One important note: these filters are not compatible with the original Nautilus CC, older Nautilus, or Triton series models. Always double-check your robot's model number before purchasing. Also, because the pleats are so fine, they may clog faster in pools with heavy leaf debris; you may need to rinse them more often than coarse mesh filters.
Overall, the SUNRRA Ultra Fine Filters offer excellent value for Dolphin owners who want premium filtration without paying premium prices. The 1-year warranty adds peace of mind, and the 4-pack ensures you're set for multiple seasons. If your robot is compatible, this is a highly recommended upgrade for crystal-clear pool water.
Pros
- Designed to replace Maytronics 9991432-R4 for many Dolphin robotic cleaner models
- Ultra fine pleated media traps both small particles and larger debris effectively
- Reinforced ABS frame keeps the filter stable during operation
- 4 pack provides good value and a longer interval before you need to reorder
- Simple maintenance with periodic rinsing every 4 to 6 weeks
Cons
- Not compatible with many Dolphin models such as Nautilus CC, M600, S200, Triton PS, and others, so check fit carefully before buying
- Aftermarket part is not an original Maytronics product, which may matter to some buyers
- No customer reviews are available yet, so long-term real-world performance is less proven
The Funmit M400 Ultra Fine Cartridge Filter is a 4 pack replacement designed for the Dolphin Nautilus CC Plus and a wide range of compatible robotic pool cleaners. It replaces Maytronics part 9991432-R4, making it a practical option for pool owners who want dependable filtration without the premium price of the OEM part.
The standout feature is the ultra fine pleated filter paper, which captures sand, leaves, hair, and other debris while maximizing surface area. The heavy duty ABS plastic frame keeps the pleats stable during operation and prevents the filter from deforming under water flow, so the cleaner maintains strong suction and consistent performance.
Maintenance is straightforward: rinsing the filter every 4 to 6 weeks is enough to keep it working well, and with proper care each filter can last 2 to 3 years. The 4 pack is especially convenient for owners who clean frequently or have a large pool, because there is always a fresh filter on hand.
The main drawback is compatibility. This filter does not fit several popular Dolphin models, including Nautilus CC, M600, S200, Triton PS, and others, so it is essential to verify your pool cleaner model before purchasing. As an aftermarket part, it also does not carry the original manufacturer branding, though the build quality is solid for the price.
Overall, the Funmit M400 filter replacement offers strong filtration, durable construction, and good value for owners of compatible Dolphin robotic cleaners. If you confirm the fit first, this 4 pack is a smart, budget friendly way to keep your pool clear all season.
Color: White
Dimensions: 10.5 x 6.375 x 10.5 inches
Package includes: 4 cartridge filters
Replaces Maytronics part 9991432-R4
Compatible with Dolphin Nautilus CC Plus, M400, M500, M200, M4, M5, Wave 65, Wave 90, C3, C4, Oasis Z5i, Aquarius XL, Liberty, Odyssey, Sigma, Triton Plus (old)
Buying Guide: What to Look for in Dolphin Ultra Fine Filters
Compatibility with Your Dolphin Model
Not every ultra fine filter fits every Dolphin robot. Before buying, double-check your cleaner’s model number and the filter’s compatibility list. For instance, the Ulticor Ultra Fine Filter Basket Compatible works with many models like the S50 and Nautilus CC, but explicitly excludes the Nautilus CC Pro and Supreme. Meanwhile, the Poolzilla Pool Cleaner Ultra-Fine Filters are designed for the Nautilus CC Plus and Supreme but not the older Nautilus CC. Always verify the part numbers and model lists provided by the seller. If you’re unsure, our Replacement Filters category has more resources to help you match the right part.
Filtration Efficiency and Material Quality
The whole point of an ultra fine filter is to trap tiny particles. Look for filters made with pleated microfiltration media or high-grade filter paper. Products like the SUNRRA Ultra Fine Filters Compatible with Dolphin use pleated panels that capture more debris than flat fabrics. The Fiitzn Ultra Fine Filtration Basket Compatible uses microfiltration technology to let fine debris pass through without clogging too quickly. A sturdy ABS plastic frame ensures the filter holds its shape under water pressure, which improves durability and hydraulic efficiency.
Ease of Cleaning and Longevity
Ultra fine filters require regular rinsing to maintain performance. Most manufacturers recommend cleaning every four to six weeks. Filters with smooth surfaces and robust frames are easier to spray clean without damage. For example, the M400 Ultra Fine Cartridge Filters Compatible from Kerneed are washable and reusable, and their premium ABS frame resists cracking. A well-maintained ultra fine filter can last two to three years, saving you money over time. For tips on keeping your pool debris-free, read our article on robotic pool cleaner filters for sand.
Value and Pack Quantity
Most Dolphin cleaners use two or four filter panels. Buying a multi-pack often provides better value than purchasing singles. The Funmit M400 Ultra Fine Cartridge Filter Replacement comes in a four-pack, giving you a full set for models like the Nautilus CC Plus. Similarly, the CLLOMAGY 9991467-r4 Ultra-Fine Filter Panels include four numbered panels that correspond to positions in the basket, making installation straightforward. Compare the number of panels included and the price per panel to find the best deal for your needs.
Final Thoughts
Choosing the right Dolphin ultra fine filter comes down to matching your robot model and prioritizing filtration quality. For owners of the S50, Active 10, or Nautilus CC, the Ulticor Ultra Fine Filter Basket Compatible stands out with its microfiltration technology and near-perfect rating. If you have a Nautilus CC Plus or Supreme, the SUNRRA Ultra Fine Filters Compatible with Dolphin offer excellent pleated filtration at a reasonable price. Both options will keep your pool water sparkling clean without breaking the bank. Remember to rinse your filters regularly and replace them every couple of years for optimal performance.
Related Guides
- Best Pool Robot Filter Basket for Algae in 2026
- Dolphin Fine Filter Basket Guide
- Dolphin Ultra Fine Filter Review
Frequently Asked Questions
How often should I clean my Dolphin ultra fine filters?
Most manufacturers recommend rinsing the filters every four to six weeks during the swimming season. If your pool is especially dirty or you use the robot daily, you may need to clean them more frequently. Regular cleaning prevents clogging and maintains suction power.
Can I use ultra fine filters in any Dolphin robot?
Not all Dolphin models are compatible with ultra fine filters. Always check the compatibility list provided by the filter manufacturer. For example, the Nautilus CC Plus uses a different filter than the older Nautilus CC. Using the wrong filter may not fit properly or could reduce cleaning efficiency. Our guide on robotic pool cleaner filters for fine debris can help you narrow down options.
How long do Dolphin ultra fine filters last?
With proper care, ultra fine filters typically last two to three years. Factors like pool usage, water chemistry, and debris load affect lifespan. Rinsing after each use and avoiding harsh chemicals will extend their life. If you notice tears or reduced filtration, it’s time for a replacement.
Are aftermarket ultra fine filters as good as OEM?
Many aftermarket brands like SUNRRA, Kerneed, and Funmit use high-quality materials that match or exceed OEM performance. They often cost less while offering similar filtration efficiency. However, always check reviews and compatibility before purchasing. Aftermarket filters can be a great value if they meet your robot’s specifications.
