a properly running unit will produce around 4-5 to 1 good water to waste water. So 50 gallons of ro/di water will produce about 200 gallons of waste. AZdesertrat has more experience with ro/di units and he could probably give you a more exact answer depending on ro membrane.
Ah, so I will definetly have to connect the waste water to a drain line. Wasn't sure if i would have to do that or simply run it to a container. With that much waste water a container is out of the question.
Yes, you will need to run the waste water somewhere. We run it to our washing machine and use it to water plants. When you think of how much water is wasted, most try to find a way of using it. Think Green!!!! It's not an endless supply!