Long Vs Short Spa Filter Cartridge Uk
Direct answer: long and short spa cartridges are not interchangeable by default. Pick the height that matches your filter housing and old cartridge, not the one that sounds like an upgrade. A taller cartridge is only better if the spa was designed for it.
The safe UK buying habit is to measure before ordering. Hydrospares treats accurate length measurement as part of identification, Hot Tubs UK describes end-cap to end-cap measuring, and One Hot Tub notes that cartridge lengths vary widely enough for height-family errors to happen.
375mm vs 275mm: what the numbers can and cannot tell you
| Height family | What to use it for | What not to assume |
|---|---|---|
| About 375mm long | Match when your removed cartridge and housing clearly support that total height | Do not assume it gives better filtration in a short bay |
| About 275mm short | Match when the old cartridge is in the shorter family and the cap style also agrees | Do not assume it replaces every listing that mentions a related code |
The internal product snapshot supports these two height families only as factual height cues. It does not support public claims about universal fit, diameter, thread, flow rating or filtration area. That matters because height is just one part of fit.
Height check before you buy
- Remove the old cartridge and measure total height end-cap to end-cap.
- Check the top and bottom cap style for open hole, closed end, handle or thread.
- Confirm the outer diameter and any printed part code.
- Reject close-enough orders when the cartridge bay has tight clearance.
Conditional next step
If your old cartridge is in the compatible long family and the end-cap details match, the site product route for the FD2007 / PWW50L / 4CH-949 / FC-0172 2-pack is relevant. If you are still checking dimensions, use how to measure a hot tub filter first, then decide whether a 2-pack or single cartridge fits your routine.