It is also important when using chemicals to have windows open.

I'm a chemical engineer and program director who left the defense industry in 2015 to work in the real estate market full time as an agent and investor.As an agent, I want to help people optimize what will be, for many clients, the biggest financial decision of their lives.I also plan to work for myself as an investor.  

I spend time daily working on it, checking the chemicals and working to keep them balanced so that there's no living thing in it so I can use it, but because of the temps and weather, I haven't been in it much anyway.

The house that has the well pressure tank also supplies the electric to the pump , if that tenant has their electric cut off , both buildings have no water . second , if there is a water treatment system that too is in the first house , who takes care of the chemicals.

When you go to a hotel, they certainly don't drain the spa every day, but I guess the difference is there is an employee to clean and adjust the chemicals every day, unlike in an STR. 

Most of my renters are workers at the chemical plants and refineries. 

I assume they are heroin addicts, but there was a strong chemical smell, so I can't rule out meth.  

With facilities such as oil refineries, steel mills, smelters, chemical plants, and power plants.

Even outside smoking brings hundreds of toxic chemicals inside that "stick" on the smoker as they come in and out.

Chemicals sold as ready to use are a huge rip off.