I've got a pool, but honestly, some of those measurements are likely to involve sensors costing thousands of dollars.
I would be most happy to be proved wrong. 
A quick search reveals a number of web sites that supply sensors such as Cynanuric Acid sensors. Rather alarmingly, I haven't found a price quoted. I'm reminded of the quote: "if you have to ask how much it is, you can't afford it" which is code for "it's very expensive".