Copied from original design:

DIY Replacement Filter Cartridge.

Darn Pool and spa filters are expensive. So I created these. Printed in 2 halves, fill with generic pillow filler or "poly fill", place both halves together and insert into your pool/spa filter holder. There you have it a cheap replacement for those expensive pool filters.

The filter this replaces is 127 mm diameter with a 54 mm hole and 13.25" (336.55 mm) tall.
You can print this if you can print something 170 mm tall.

Some of the numbers this filter are know as are :
FC-2375
PRB25

C-4326

Now the good stuff:

No need for supports. It is actually an entertaining print as there's a ton of (easy) bridging throughout the job.

Use whatever material you like that you have reasonably tuned for bridging, but PLA is probably not a good choice. I printed mine using ApolloX ASA with a .6mm nozzle and .36mm layer height and each half took about 8 hours (around 17 hours total print time).

I elected for no infill by using 3 walls (ends up being 5 walls on the railing @ my resolution) and accounts for about 70% of the time printing spent on perimeters. I think this helps prevent the inner pillars from being knocked down in between railing layers, but this likely varies by machine. Do what you think is best if you know your machine.

I should also note this is being stuffed with Filterball blu balls.