Did the client request this? Some people are extremely sensitive to smell, so I wouldn't if they didn't specifically request it.

If you still want one, I would just use a plug timer for the auto on and off. Here's a few to look at:

https://www.amazon.com/Mechanical-Outlet-listed-Minute-Increments/dp/B01MA456OZ/ref=zg_bs_495340_9?_encoding=UTF8&psc=1&refRID=QXXE0S4HRVAMY9Z7FZRP

https://www.amazon.com/Digital-Programmable-Socket-Energy-Saving-DT-01/dp/B00WHPNON6/ref=zg_bs_495340_5?_encoding=UTF8&psc=1&refRID=QXXE0S4HRVAMY9Z7FZRP

As for the diffuser, there are many attractive ones that can run for most of the day.

This one runs for 7-8 hours: http://www.bulkapothecary.com/sparoom-lotusmist-ultrasonic-diffuser/?gclid=Cj0KEQiA4JnCBRDQ5be3nKCPhpwBEiQAjwN1bhyzFpOFPBixeqBLlvjomkW_VWOj-SpdPIKz7PU5qsoaAkFP8P8HAQ

This one runs for 6 hours: https://www.amazon.com/ArtNaturals-Shut-off-Changing-Essential-Diffuser/dp/B010GIUVYK

i agree. a lot of people don't like certain odors. How about just natural smells? Flowers, pine tree, pine cones, even those cinnamon things (although some people may not like that either!) If it's not overwhelming, then it should be fine. again, non-overwhelming. just a very faint, barely discernible smell.

....ok. So here would be MY beef with something like that: the smell. As someone who lives a "low odor" life (no body products other than deodorant...no scented candles, non-scented moisturizers, etc) I find heavy smells to be offensive.

I'm an avid spa goer...as a woman (I know...not many know that Cancork Floor is written by a woman) I LOVE spas....but I will run away if the scents are TOO heavy. My massage therapist has to switch to an unscented cream rather than scented products. Essential oils cause my asthma to flair up.

Any scented product can be light...or heavy. It depends on the product, the amount and the method of diffusion. Scented oils can be very heavy if allowed. And people with breathing problems can have issues with heavy smells. Asthma and COPD being two of the 'big boys' in the world of medicine.

I'm also a migraine sufferer. My migraines can be triggered by heavy smells. Again, another reason why I find perfumes to be offensive. Walking through the mall can be torture.

I know what you would like to create, and I wish you well with your project. Just keep in mind there is a growing amount of people who like spas to be FREE of irritants...not full of them.

I wish you all the best. Namaste.

There are some diffusers that have an intermittent mode. More like one of those glade things that just puffs out scent on a timer. That might be a better option, since it would be less strong. I still vote no to the whole thing, though.

There are tons of diffusers out there that automatically shut off and run for 6-8 hours. Google essential oil diffusers. I am a massage therapist (former business owner) and while I did not use the new diffusers, I did use those plug in candle holders like the Scentsy. I just put in water with a few drops of EO. It was not overpowering. Of course it depends on the scent you use and the amount. I would use un uplifting single scent or a blend for calming and relaxing. Citrus always is good, as well as mint. Lots of spas use lavender, but I find that cloying. Florals are usually too heavy for general use. Search for massage therapy supplies online. They have professional equipment for use in clinics. I'll give you a little hint.....also have a small air purifier in each treatment room to clear out any fragrances in between clients; that way if the next client is sensitive to a particular scent (or all of them), the scent will dissipate before they settle in. Then the massage therapist can custom blend a scent just for that client without traces of any other scent.

MassageWarehouse.com

Bodyworkmall.com

MassageKing.com