What types of resistor? did I need to use it

[johnerrington]

The circuit is too complex to analyse from the picture, we need a schematic.

How to make a schematic you can post.

When you submit a question on the forum you will usually need to add a schematic (circuit diagram). The tutorial that follows will explain some ways to create a useful image; however lets start by explaining how to add the image to your post. Its easy. Having created the image all you need to do is : Save the image somewhere convenient - maybe your desktop Start your post, and place the cursor (insertion point) where you want the image to be shown; [upload image to forum] 3: click th…

You will also need to give more details of your setup eg what is ORP and what is the nature of the "tube", and the solution (to be sure that silver counts as inert).

I see you are using a Uno. Can you post your code please.