I'm new myself into Arduino and microcontroller programming and have gotten myself waistdeep into the subject , but i don't think there is a ready-made starterkit for what your asking about.
There is however several manufacturers that provide such peripherals for the Arduino. PH shields ( a shield is a board you put ontop of the Arduino that extends it's functionality) like the one i got yesterday Arduarium controller
or another simpler shield from the same guy BNC sensor shield
You also need a PH Probe like these
I ordered a couple of these probes to experiment with but similar one's can be found elsewhere, in different priceranges and qualities.. ( i'm not really sure if the one's i ordered is going to handle being constantly submerged in water but they were cheap.. so it's no big deal if it doesn't work)
Heres another probe-kit with a PH shield included as well as calibration liquids and example-code. Atlas-scientific PH kit
Here's one type of temp sensor
for water but these can be found elsewhere too.. and the temperature sensor-thingy is very easy to setup with a few tweaks into Arduino programming.
In the end it's a bit of copying and pasting of code, tweaking stuff to get the best result and getting the sensors properly attached to wherever you need them.. but that should be the fun part, right?