How many came in the case?
I don't know, I've never bought a case of them.
I keep two on the shelf - they don't have a "use by" date - and every once in a while I get somebody who is on a well, or has some other water issue which is out of the ordinary.
Every couple of months people come in after having read the owners manual asking why I didn't include one with their new spa. I ask if they have bad tap water, show them the $50 price tag, and they are usually fine.
I also have a couple of these - which are strictly for sand, dirt, grit and such in the fill water:
I use one because my garden hose sits in a puddle sometimes if we get a lot of rain, and it can get junk inside of it. Also, it helps hold the hose in place if I don't have the cover down, and it keeps the hose from scratching the bottom of the spa.
Those little filters are about $15.
8-)
