What Aquariums Fit the N-Clear M? Complete Tank, Sump & Adapter Compatibility Guide

Quick answer: The N-Clear M drops into most standard 4-inch filter sock holders without an extra adapter. Larger AIO and rectangular openings may need a model-specific N-Fit M Adapter: M1012 for Innovative Marine 30/40/50 AIO, M1212 as an optional replacement holder for IM SR 60/80/120, M1216 for Waterbox 65.4 or Waterbox 50 Peninsula, and M1218 for most 7 × 4.5 inch rectangular sock openings such as ESHOPPS Mariner.

First identify the type of opening

A patent-pending cone-style fit instead of a sump rebuild

The N-Clear M uses a patent-pending cone-style fitting system. The interface is designed to settle naturally into many existing 4-inch filter sock holders while the compact lower body occupies the space where the sock already lived. One fitting approach can therefore accommodate small differences among standard holders without asking the owner to rebuild the sump around the filter.

This becomes more valuable on a large system. Some large single-body fleece rollers need a wide dedicated bay, drain-plumbing changes, removal of a sock tray, or changes to baffles and sump layout. M takes a modular approach: keep the existing sock positions, drop a compact M into each active path, and synchronize additional Extensions from one controller. A properly planned multi-M setup can serve systems around 180 gallons without treating one oversized roller as the only way to get enough mechanical-filtration capacity.

Confirmed direct fits: no extra N-Fit M adapter

The systems below use a standard 4-inch filter sock holder or an original 4-inch sock adapter that supports the M directly. The tank name still does not replace a physical clearance check, especially when plumbing hangs over the sock plate.

N-Fit M adapter table

Clearance checks that still matter

N-Clear M has a 3.55 × 2.9 inch body footprint and is 15.75 inches tall excluding the new fleece roll. The product's chamber guidance and above-plate access serve different purposes:

• Chamber/support check: for nonstandard openings, plan around at least 4.3 × 4.3 × 7 inches of usable chamber space or the exact approved adapter geometry.
• Above-sock-plate clearance: keep at least 4 × 3.5 × 9.8 inches free of pipes, valves, cables, braces, and cabinet obstructions where the upper filter and roll must be accessed.
• Water depth: the body can operate through a broad submersion range, but about the bottom 4–5 inches submerged normally improves flow and noise. A useful starting water depth above the sock plate is roughly 0.4–1 inch.
• Water blockers: most M installs use the appropriate front water blocker to reduce bypass. The IM 30/40/50 M1012 setup is the exception and uses the bare adapter.

How many N-Clear M filters should a multi-sock sump use?

One M is rated for up to 800 GPH. A Main + Extension pair is rated for up to 1,600 GPH. The M controller can synchronize additional extensions, but the number of filters should follow the number of active sock paths, return flow, tank volume, and bioload—not only the controller's connector capacity.

For large 180–200 gallon systems with three active 4-inch sock openings, three M filters are generally the stronger arrangement. This is the core modular advantage: add filtration at the existing sock positions instead of cutting the sump to create one oversized roller bay. If only two openings are filtered, cover the unused path so water does not bypass the fleece. The N-Fit 4-inch Filter Sock Cover is made for that job.

Known non-fit or conditional situations

• Small nonstandard AIO openings: an AIO opening smaller than roughly 4.4 × 4.4 inches and without a standard 4-inch sock holder is not a current M fit.
• Red Sea rear-chamber AIO layouts: current built-in rear chambers are not supported. A Red Sea tank converted to a sump with standard 4-inch socks uses the direct M sump path.
• Missing factory cradle: JBJ and similar direct-fit claims assume the original 4-inch sock cradle remains in place.
• Overhead plumbing: an opening can be correct while a drain, valve, or pipe blocks the motor or prevents roll changes.
• Modified chambers: cutting out a tray or holder changes the support geometry; remeasure rather than relying on the original tank model.

Frequently asked questions

Does N-Clear M fit any 4-inch filter sock?

It fits most standard 4-inch sock holders, but confirm the holder is stable and there is enough space below and above it. Oval openings, overhanging drains, or removed cradles can change the result.

Does N-Clear M fit a Red Sea REEFER sump?

Yes, Red Sea REEFER sump systems are a supported M path. Check overhead pipe and valve clearance. Do not confuse them with Red Sea rear-chamber AIO layouts, which are not currently supported.

Which N-Clear fits Waterbox 50.3 versus Waterbox 50 Peninsula?

Use N-Clear Nano with S80120 for the current Waterbox 50.3 rear-chamber AIO. Use N-Clear M with M1216 for the older Waterbox 50 Peninsula.

Do Innovative Marine SR 60/80/120 tanks need M1212?

Only if the original 4-inch filter sock adapter is missing. With the original holder present, N-Clear M fits without buying M1212.

What if my sump has three sock openings?

Use a filter in each active opening when capacity and layout justify it, or cover unused openings to prevent bypass. The M controller can run synchronized multi-filter setups; see the N-Clear M User Guide for connection diagrams.

What should I send for an unlisted opening?

Send the exact tank and sump model, full chamber measurements, and white-light photos following the adapter measurement request guide. Include both the opening and the space above and below it.