Nature2 cartridges - I want to post this as a Public Service Announcement. No real news here or anything, but I found another Nature2 cartridge which had been left in the tub for about five years, and had finally come apart, dumping it's contents into the plumbing. Happened to be on a HotSpring Portable Spa, so it went into the small circ pump and I had to remove it to clean and clear it. The pump lived...
I have seen this happen quite a few times. My delivery crew used to insert the "Silver Ion Cartridge" into the appropriate filter on set-up, and the customers didn't see it go in, or didn't hear that it needed to be replaced, or they moved into a house with the tub already up and running, etc. There is nothing wrong with the product as far as I'm concerned, but do be aware that they didn't build the things to sit in your tub for this long!
Also - the yellow cartridges don't have the little shoulder on them which keeps them from sliding down into the plumbing when used on a Watkins product. In the HotSpring models, that can allow it to drop down and block the flow to the circ pump. In the Tiger River and Limelight models, it can rattle around in the larger outlet - the little extension sticks can come loose and go right to the pump. Yes, the plumbing on those models is large enough to allow that to happen. So if you are using a yellow stick as opposed to buying the gray ones from a Watkins source, (as in - if you are not supporting the loving, caring dealer who you got your wonderful spa from... :-)) be careful to get the extension sticks snapped on tight! They now have a little hole in the side and a small peg sort of thing which need to be engaged to keep them from coming apart.
There ya go!