Hi, I'm making a project with arduino that monitor my reef aquarium. So one of the things that I have is PH monitoring. To do that, I have the Atlas Scientific Ph Stamps: http://atlas-scientific.com/product_pages/embedded/ph.html
My connection is like this:
When I mesure the PH inside a bottle or a glass it measures the PH very precise, but when I place the probe inside my aquarium it give me wrong values. I also noticed that when I turn off my watter pumps in the aquarium the reading is fine, but when I turn the pumps on the problem appears again.
I have read a lot about ground loops (http://www.all-about-ph.com/ground-loop-problems.html) and interference with pumps and noise that is inducted into the PH probe but I don't understand what I have to do/buy to solve this.
So for my understanding until now I have to buy DC-DC power converter and an optical data isolator but I don't understand what chips to buy and how to connect them im my arduino conection like I showed. For example this other controler show this: http://www.splatco.com/sx10507.htm
This uses a transformer isolated DC-DC power converter, and an optical data isolator, to ensure there is no metallic (ohmic) connection between the pH probe and the controller. This isolation eliminates the interference that can be caused by ground loops.
Please give me some guidance about this. If what I think it is, is correct and how can I solve this issue. Thank you vey much.