Pool & Hot Tub Filter Guides
Short, practical guides to the parts of pool and hot tub filters that trip people up, from measuring a cartridge when the printed number has worn off to making sense of the tangle of cross-reference part numbers. Written by the same person who compiled the data on this site.
How to Measure a Hot Tub Filter Cartridge
The printed number wears off first. Here is how to measure the three things that actually decide which cartridge fits.
Read the guide →Pool and Spa Filter Cross-Reference Numbers, Explained
One cartridge, five part numbers. What Pleatco, Unicel, Filbur, and OEM numbers mean and how they line up.
Read the guide →How Often Should You Replace a Filter Cartridge?
One to two years is the rough answer. The pressure gauge is the honest one. Here is how to tell when a cartridge is actually spent.
Read the guide →How to Clean a Pool or Hot Tub Filter Cartridge
The 45-degree rinse, when to soak, and the two shortcuts that quietly ruin cartridges (one of them is the pressure washer).
Read the guide →Cartridge vs Sand vs DE Pool Filters
Three ways to filter a pool, compared: how fine each one gets, what each costs you in upkeep, and which fits which pool.
Read the guide →Are Generic Filter Cartridges as Good as OEM?
Usually yes, sometimes with a catch. Where generic cartridges match the original, where they can differ, and how to buy a good one.
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