Wow the thread came alive over night. Well, for KD a typical bubbler/DWC is generally self contained in one bucket or a rubbermade tub with multiple net net pots growing multiple plants, if you want to connect other buckets to a main reservoir where you can mix you're nutes and check PH and refill water and so on than this called a recirculating DWC. The Water farms can be an individual unit consisting of one bucket or can come in an 8 pack with a controller and main reservoir whir you add nutes and water so it can be distributed to all of the buckets. But once the water/nutes leaves the controller in the Water Farm 8 pack to go to the buckets it does not recerculate back to the controler so it is not a real recerculating type system, but can be modified to be one.
Weed Hound I think it was you who asked about mediums, around here in my state people use lava rockes the red kind, but it needs a peroxide bath before using, know the measurements of water ratio if anyone is interested. Transplanting, well some people when transferring in any hydro system with net pots will sometimes start off in small net pots with their grow medium and as they transplant will just take the whole net pot and place it in a bigger one and have no problems.
Xcrispi sounds like you had a pretty good run in your old set up, hope that this run is comparable. As for your water temp problems I see a couple possibilities, 1. If you did modify your system to a recerculating system, can't remember if that was you, use an aquarium heater in the main controller. 2. With 8 packs, you could get 8 heating pads to put under each bucket, I know it sounds like a pain and probably would be, not too mention raise your electric bill some, but it is just a suggestion.
Well Adieu