Van Life: Forever Shower Help Plz

Hey, whoever you are, I hope youre having a sweet day or night!

I can't update status on my Mechen MP3 player, because the screen blocked the "save button" so I will post a blog instead. 

Okay, so I am doing semi van life where you live out of your van part time. I need to set up a recirculating shower in my 1999 astro van that is compact and easy to store away when not in use. 

Is it a okay to use one of these under the sink osmosis filtration systems to filrate my shower water? I have 300.00 to spend on the NU Aqua, or maybe the Express water filtration system. 

Has anyone ever made one these forever showers?

Thanks for reading and any input will help.