Wow, so I have been doing some research and I figured I'd post my finding in case others were thinking about doing the same thing. First off this is hardly a new idea. Several companies in Europe and the USA are or have tried kickstarter programs to make these. One company in Europe makes them and they are cool but stupid expensive. So after getting some responses from manufactures I have some how and why's. Basically if you design a shower the water has to be drinking level safe. This certification level changes dependent on the state. California has the most restrictions and it makes it too expensive to bring a product to market. Hey, most of us have showered in a place you can't drink the water. Past that my tub model still holds true. Just because you use 30 gallons of water in a tub the soap, shavings, and "parts" washing gets diluted but is still not drinkable. Tubs are legal, showers are not. Sigh! Ok moving forward Large Koi pond filters are the cheap and easy answer to the filtration issue. Most have small, built in, UV sterilizing lights . They will handle the pressure and volume and require an external pump. Most of the tropical tank fish filters have an internal pump and it is less than adequate. I will be adding an additional inline UV lamp, does two jobs. Kills bacteria missed by the first small light because of increased rate of flow. Adds a little thermal energy to the water and slows the cooling process. Boil half a gallon of water and mix in another 3/4 gallons of temperate water to a base with a six inch rise. Turn on the pump, and wait till he oxygenitics shower head is the only thing adding air to the system and enjoy. Should be clean enough for the cats I roll with. One additional benefit of the Koi pond filter is it has a bypass for draining the swamp. Flip a switch and the water gets diverted to an outside grey container under pressure sucking the system dry.
SO with all this information, any concerns questions or ideas?