Yet another water system thread

First post on the Arduino boards, howdy.

I've been lurking on both the Arduino and rPI boards for a while now and have done a fair bit of Googling prior to making a post as to avoid asking redundant questions.

My hardware goal - monitor four pressure points on my homes well water system (schrader valve on the pressure tank and inline with three other analog gauges) and detect when two pressure switches operate (your typical 30/50 square-d 9013fsg2j21 240VAC) and detect the level of fluid in my chem feeder's supply tank

My software goal - collect data points using RRD so I can both display the data on an LCD in my water room but also be able to view over my local network. When the chem tank gets to a certain level, SMS or email me a notification so I can act accordingly.

Just a preface, I have sulfur in my water, hence the chemical stuff and a pre-treat feed for outside water and post-treat feed for in house.

With that out of the way, my questions are as follows:

  1. lots of pressure transducers out there, is anyone familiar with or can recommend ones that will hold up in a chlorinated water environment

  2. sensing 240 VAC... i dont need to control the switches, i just want to know if they are on or off... the primary pressure switch is fed from the panel... the secondary switch (that engages the chem feeder) is fed from the load side of the primary

  3. tank level in, again, a caustic liquid (chlorox bleach) - tank is ~36" high 18" wide

just a background, this is setup such that when outside water is being used (drawn before the injection site) the chem feeder doesn't just dump chlorine into the house water that isnt being used... the secondary switch is energized when the main switch calls for the pump and when the house pressure drops accordingly it will turn the feeder on.

I'm favoring going with the Arduino as it has a built in ADC where as the PI does not - outside of that I haven't made other considerations.

The rest of this I can likely gleam from other projects online, etc (coding, display driving, etc) but really looking to get some solid advice on the sensors.

If I can't find sensors that will hold up in a chlorinated environment (MTTF ~12 months) then I'll likely skip it as I really don't want to add something that will add more up-keep to the system - the goal of this is to simplify things but I acknowledge it won't be lights-out in perpetuity as chlorine kills everything eventually.

Thanks =)