How to Identify a Spa Filter Cartridge

A cartridge reference is easier to review when dimensions, end details and existing identification are recorded together. A photograph of the side alone leaves important questions open, even when the cartridge looks similar to one in a catalogue.

Begin with the reference you already have

Look for an existing part number, equipment reference or supplier drawing in your records. Include the full reference and identify where it came from. If there are several document versions or previous replacements, say which part is currently being used.

If no identification is available, a supplier can still begin by reviewing photographs and measurements. Keep unknown items clearly marked rather than selecting the nearest-looking catalogue item and assuming a match.

Record body length and outside diameter separately

Use the G01 diagram as an information checklist. Record the length of the cartridge body and its outside diameter, and state the unit used. Describe where the length measurement starts and ends.

Handles, necks, fittings or other projecting parts should be recorded separately. Ask the supplier whether its quoted length includes these features. Two measurements with the same number are not directly comparable if they use different starting points.

Show both ends

Provide separate top and bottom photographs. Include the opening shape and any handle, extension or fitting. If an opening or fitting needs to be measured, identify which feature the measurement refers to and ask the supplier to confirm its convention.

Do not infer a thread, internal core or filter medium from a side view. Pleated or mesh-surface appearance is a visual reference; a specific manufacturing process needs supporting product information.

Include the application

State the spa or equipment reference where known and explain whether the task is a replacement, a supplier comparison or a new requirement. Tell the supplier which interfaces must remain unchanged and what evidence you need to review the proposed cartridge.

Information checklist

• Existing part number or drawing, where available.
• Body length and outside diameter, with units.
• The measurement starting and ending points.
• Separate top and bottom photographs.
• Handles, extensions or fittings recorded separately.
• Equipment or installation reference.
• Indicative quantity and the question to be resolved.

Before accepting a proposal, compare the supplier’s confirmed dimensions and end details with your reference. Similar appearance on its own does not establish interchangeability.

Next step: Visit Filter Cartridges, then send your reference through Contact. Mark any dimension you have not been able to confirm.

Frequently asked questions

What information identifies a spa filter cartridge?

A part number or equipment reference if you have one, the body length and outside diameter with the unit stated, where each measurement starts and ends, and separate photographs of the top and bottom ends. Handles, necks and fittings are recorded separately from the body.

Can a cartridge be matched from a photograph alone?

No. A side view does not show the opening shape, the end fittings or the media construction. Pleated or mesh-surface appearance is a visual reference only, and similar appearance does not establish interchangeability.

Why record body length and outside diameter separately?

Because one number cannot describe both. Suppliers also differ on whether a quoted length includes handles or projecting parts, so the measurement starting and ending points have to be stated with the figure.

What if the old cartridge carries no part number?

A supplier can still begin from photographs and measurements. Keep the unknown items marked as unknown rather than choosing the nearest-looking catalogue item and assuming a match.