Product guide
Dolphin m400 ultra fine filter
Double-check before purchasing
- M400 has had several production revisions — verify compatibility with your specific serial number before ordering ultra-fine baskets
Compatibility
The Dolphin M400 ultra-fine filter basket fits the M400's top-load filter housing and is a direct upgrade from the standard fine-mesh basket. It is designed to capture algae, fine sand, and fine particulate debris.
How to Verify Fit
- Confirm the basket is labelled for M400 or in-ground Dolphin models — not for the E-series above-ground lineup
- Ultra-fine mesh appears denser and more opaque than the standard fine basket when held to light
- Both baskets in the M400's dual-basket housing should be the same mesh grade — do not mix ultra-fine and standard
Common Mistakes to Avoid
- Installing only one ultra-fine basket alongside one standard basket — uneven filtration and suction imbalance between the two chambers
- Not cleaning after every cycle — ultra-fine mesh clogs faster than standard mesh
- Using ultra-fine baskets in a pool with heavy organic debris (leaves, pine needles) — they will clog after one cycle
When to Replace
Rinse after every cycle. Replace both baskets simultaneously when either shows mesh damage. Due to finer mesh, replace at least once per season under regular use.
Buying Tips
Purchase ultra-fine M400 baskets as a pair so both chambers are matched. OEM Maytronics baskets are the safest option. For third-party, confirm explicit M400 compatibility and check reviews for fit quality.
Where to Buy
Find compatible replacement parts from these retailers:
Frequently Asked Questions
Does the M400 ultra-fine filter require more maintenance than the standard filter?
Yes — fine mesh clogs faster. Plan to rinse after every cycle rather than every other cycle.
Should I switch the M400 to ultra-fine year-round?
Only if your pool consistently has fine particulate issues. For seasonal algae problems, switch during those periods and revert to standard mesh when algae is under control.
Are M400 ultra-fine baskets sold in pairs?
Some retailers sell them in pairs; others sell individually. The M400 uses two baskets, so you need two matching units.
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