The good thing, was that she turned out fairly intelligent and graduated with zero debt as a chemical engineer. 

We spoke to our local pool company, and they would come out every two weeks to monitor salt and other levels, backwash the system, and any of the other specialized maintenance tasks.Our pool is salt water, so it doesn't require quite as much of the chemical up keep, but how do you manage the more frequent cleaning?

If you have a tenant that is dealing with corrosive chemicals, it can eventually eat away at framing members so be careful on who you lease to and what their plans are.

Graduating in the Fall with a BS in Chemical Engineering.

She had rented for over 10 years with the same landlord in a community that was deemed unsafe due to chemicals in the soil. 

If you buy used, you need to check for hazardous chemical residue in the unit, if you want to use for housing. 

The dashes are how they inject the chemicals into the lumber.

Horrible place to put a pool.If you can run year round, maintain good chemical balance and stay on top of the maintenance it shouldn't be as bad. 

Agreed- 2 tubs equals double the work, footprints, cost, pumps, chemicals, cleaning etc etc 

IF $ feasable, tear off the existing layers of shingles, install a good THICK and SYNTHETIC underlayment (like Ice/Water barrier, not cheap synthetic) and not just 2 layers of black felt; insulation boards; then the metal roof.