We had a Chemical Engineer from somewhere in Africa.

I saved two, thankfully.You can get a chemical, I forget the name, and put it in the pool so when the kids (or adults) pee it will turn BLUE and they are SOOO busted!

It is reasonable to ask your tenant to dip out leaves from the skimmer and pool but use a pool service for everything else, including chemical maintenance and equipment.

What do you use to test the hot tub for safety and to adjust any chemical levels? 

The problem with our city is that the local chemical & energy industry has diminished over the last 10 years going off shore. 

That includes removing one layer down to the wood sheathing, installing ice/shield on eves and valleys, new drip edge and synthetic paper, ridge vent, 40 year dimensional asphalt shingle and new flashings on walls and chimneys and should include a 20 year workmanship warranty, that’s what I offer.

I'm considering buy some property near a new chemical plant construction site and turning it into an RV park to house the construction workers.

Keep in mind, if you keep it as a car wash biz, that revenue should cover costs of water, electricity, chemicals, etc as well as the building maintenance.

I have been working in chemical plants (project scheduler / "excel guy") for a few years but the uncertainty and constant relocating can be draining. 

Spas would also require a lot of attention for chemical adjustment and cleaning.