Swimming pools blog

I am about to have my first ever pool constructed. Hence my questions
may sound dumb to most members. Anyway, here we go:-
(1) How do I go about having the pool heated with solar? Here in
Montenegro, a heated pool would extend the swimming season by nearly 3
months.
(2)I have seen in a pool a layer of ping-pong balls instead of a
cover. Is this a good idea?
(3) What is the best method for disinfection without chlorine (my wife
is allergic against that stuff)? Some say electrolysis, others say
salt water (which would appeal to me, as I love swimming in the sea)?
Thanks in advance for your advice
Ernst
mumarquise