I recommend you call Hanna they sell a meter that is better then any you will find in a grow shop for a third of the price. Its the Hanna 9044 and they can direct you to your local distributer who will mail it to you for 120 dollars. It tests ph temp ppm and microseimens. Top notch continuos monitorer. I called up Hanna a few months ago to see if they could make one with a remote control and I was told about this new meter they are putting out which can be checked via telephone. Its 540 usd and the phone attachment is an extra twenty. Sure a bit pricey but tell me thats not cool. The people at Hanna are very nice and will help you with your needs.
One love
c