What you are running is NFT. You don't strictly NEED an aerator in that system because of the constant water tumbling over the medium, but it won't hurt one bit. Don't let your plants get too big; those 6" pots can support plants through flower IF you start them on 12/12 before they hit about 6"... otherwise, you will get some issues with root mass taking up too much of the space in the pot that was supposed to be free for water to flow, and that can translate to rot.

I'd run Cannazyme according to instructions in a system like that, and also do frequent res changes.