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Or the other side of the coin is some people are just plain LAZY........
Friends, I have had to do some non-warranty service work on five spas which all had the same problem: the Nature2 cartridge 'let go' and filled the jet pump and/or circ pump up with little spheres and with plastic debris.All of these tubs had owners who either didn't have any idea the thing was there, or just figured it wouldn't hurt to ignore the cartridge for three years or so...So, here's a 'heads up.' If you leave your Nature2 cartridge in place for years, it may very well fall apart and that may be a big problem.They are designed to be in the water 4 months, not four years.
maybe it's silly to say this, BUT.....maybe they didn't get the lowdown on what the n2 system is, and replacement of it, etc from the dealer when they bought the tub? Were they purchased from the same dealer, perchance?
chas,In your case are you referring to Nature2 cartidges in Hot Spring spas or Hot spring's private label AG+?We have had Nature2 cartridges improperly installed in Hot Spring spas ending up in the jet pump.Never had an issue with the deteriorating cartridges. Maybe we have our customers trained to change their cartridges.