Nice idea, dont know how you would explain it to the wife though, Er honey I am going for a paddle in the hot tub with the boys! 
That's up there with Webbers ridiculous wave pool ideas !
Interesting aside though, in Australia, any body of water which holds or has the ability to hold 30cm of water depth has to comply with the swimming pools act 1992 so it would need a cover (like a spa) or requires pool fencing to protect kiddies.
Just saying. 
Maybe you could throw some washing powder in along with your dirty clothes and kill two birds with one stone.. 
DJ
