MJ,
Shampoo dilution will not be a problem but you must have adequate flow through the system. The commericial resturant sink type hose and spray nozzle will not allow this to happen. Therefore, after many many attempts to get a straight answer from my supplier and national pride about my pressure/shampoo suction problem I went to Lowes and purchased and 25' 3/8" ID spring type garden hose and a heavy duty gun type nozzle for about $25 and it works great. Plus it's long enough to spray off the whole unit for routine cleaning.
I set mine to run 10 min for $5 or 5
tokens. Free washes to the local Humane Society, canine rescue, and or animal shelters are a great cheap way to get the word out. Also a trip to the local dog park with a pocket full of free
tokens pays off too. I learned the dog community is well informed and tight knit so if you can tap into the network by sponsoring calendars or their publications, that will be the most return for the least amount of cash.
Also, good exterior signage visible from the travelway is also cost effective.
If you have a self contained ss cabinet with the dryer and shampoos in it from national pride, it will most likely it will not come with air intake holes and the dryer will burn out in a few days. Drill 4-3/4" ID holes near the intake on the dryer and it will work fine.
The
door in the front of the bill/
coin acceptor and selection dial is not physically attached to the rest of the housing so take great care in opening it to pull the cash as until you get the hang of it, the front panel will fall completely out and royally screw up the connections to the whole world. After you get through swearing, it takes a while to undo that one!
Depending on how far your hot water supply is from the unit a small recirculation pump on looped hot water piping helps a lot. By the time your customers finish disinfecting the tub the water is warm, in my opinion this is important.
If I can think of anything else, I'll post another reply. Until then, best of luck !!!