Water TDS Measurement

redneckengineer:
I've done some experimenting with my arduino , breadboarded a circuit, wrote the code, and tested it with my oscilloscope. I don't think the arduino has the right kind of outputs...watching the oscilloscope the arduino pins seem to drain to ground then set to INPUT.

That behaviour is presumably not what you intended, so there is something wrong with your hardware or software or both. We'd need to see your circuit diagram and software to have any hope of guessing what's wrong.