awsome!! also i have looked at many videos and all of them have to DI chambers hooked up to a faucet however that wouldnt be using the clean water, what pump would I want to use since it is a very low pressure that goes into the DI chambers?
You can check out the booster pumps that are typically sold as accessories for RO units. Bulk Reef Supply sells one. They are pretty standard in size and I would hook it up leading into the RO unit which then would run into the DI chambers.
I see those deionizing units people use to wash their vehicles with. Depending on how much water you plan to be using and the size of the unit or amount of resin it holds along with how clean or dirty your tap water is will determine the longevity of the resin.
If you're goal is to have ZERO TDS (it should be) and you want to gain longevity out of your resin then you'll definitely want to filter it first.
Invest in a TDS meter if you haven't already. It will help eliminate most of the guess work as to then it's time to change resin or filter cartridges etc.