CX580XREPAK4 vs. CX880XREPAK4: Which Hayward SwimClear Cartridge Pack Fits Your Filter?
We get this call at the shop all the time. Someone opens up their Hayward SwimClear filter, sees four dirty cartridges, and orders a replacement 4-pack online. A week later they call us because the new cartridges don't fit. The problem is that Hayward sells two very similar looking packs, the CX580XREPAK4 and the CX880XREPAK4, and they are not interchangeable. This guide explains which pack goes with which filter, how to check what you have, and when it's actually time to replace instead of clean.
What's the difference between the CX580XREPAK4 and the CX880XREPAK4?
The difference is size and filter area. The CX580XREPAK4 is a set of four cartridges with 325 square feet of total filtration, made for the smaller SwimClear tanks like the C3030. The CX880XREPAK4 is a set of four larger cartridges with 425 square feet of total filtration, made for the bigger C4030 size tank.
In photos they look the same. Four white pleated cartridges, same style end caps, same general shape. The larger CX880XREPAK4 cartridges are simply taller, and that extra height is where the additional filter area comes from. You can't eyeball the difference from a product listing, which is exactly why so many people order the wrong one.
How do I know which SwimClear filter I have?
Check the label on the side of your filter tank first. It lists the model number, and that number tells you everything. A C3030 series tank takes the CX580XREPAK4. A C4030 series tank takes the CX880XREPAK4.
If the label is faded or gone (sun does that after enough seasons), pull one of your old cartridges and measure it. Then compare your measurement against the specs on the product page for each pack. You can also look for a part number printed on the end cap of the old cartridge. If it starts with CX580, you need the CX580XREPAK4. If it starts with CX880, you need the CX880XREPAK4.
Still not sure? Take a photo of your tank label and your old cartridge and send it to us. Matching parts is what we do all day.
Can you put the bigger cartridges in a smaller filter?
No. The CX880XREPAK4 cartridges are too tall for a C3030 tank, and the lid won't seat properly. Forcing it risks a bad seal, leaks, and unfiltered water bypassing the cartridges entirely.
Going the other direction is just as bad. Short cartridges in a tall tank leave a gap, water takes the easy path around the media, and your filter stops doing its job even though everything looks assembled. If your filter pressure barely rises but the pool stays cloudy, a wrong-size cartridge is one thing worth checking.
How do you know when SwimClear cartridges are worn out?
Worn cartridges show a few clear signs: high filter pressure that comes back quickly after cleaning, cloudy water that won't clear up, pleats that look frayed or crushed, and cracked or brittle end caps. If you're rinsing the cartridges more and more often just to keep the pressure down, the media is at the end of its life.
Cleaning only goes so far. Each rinse removes debris, but the fabric itself slowly loses its ability to trap fine particles. Most cartridges give you a few seasons of solid service with regular care. Once cleaning stops bringing the pressure back to normal, no amount of hosing will fix it. That's a replacement, not a maintenance problem.
Should you replace all four cartridges at once?
Yes. Both the CX580XREPAK4 and the CX880XREPAK4 come as complete 4-packs for a reason. Mixing one new cartridge with three old ones forces most of the water through the fresh one, wearing it out faster while the old ones keep restricting flow. Replacing the full set keeps flow balanced across all four and gets you back to full filtration in one shot.
The bottom line
Match the pack to the tank. C3030 series filters take the CX580XREPAK4 with 325 square feet of filtration. C4030 series filters take the CX880XREPAK4 with 425 square feet. Check your tank label or old cartridge before you order, and replace all four together. Both genuine OEM packs are below.
Not sure this is the right part for your problem? Reach out and we will help you figure out exactly what you need before you spend money on the wrong thing.