I bought a ec sensor recently and I am having a little bit of trouble figuring out what the wires connect to. One of them is gnd, I know where that goes. The other connects to a battery, but I don't know where the other two go. The website I bought it from says they are communication wires, the yellow being a 485-a, and the blue being a 485-b. Can anyone tell me what these mean?
Yes, it's the RS-485 serial protocol. Wiki has a good overview.
Can you please clarify? Where can I find it on wiki?
In the search box.
To use an RS485 sensor with Arduino, you will need an RS485 to TTL serial adapter.
Here is one of several possibilities.