It's tough to say how many watts you'll need because a lot depends on how well you are able to insulate the tank. You will definitely want lids since a huge amount of heat would otherwise be lost if you had an open top.
I personally wouldn't go with less than 2 watts per gallon, so you would need the Ranco Temp controller that requires 2 dedicated circuits (two 15 amps circuits, would work, but two 20 amp circuits would be better).
But having said that, you may be better off heating the entire room if you are going to have multiple tanks running.
The room my tank is in is unheated. To give you and idea of what you might expect if you were to use electric aquarium heaters only: temps in my fish room get down into the low 50s during the coldest winter nights. During colder winter months, my heaters would come on for 5 or 6 hours per day to maintain 78F, which translates into around 325kWhrs per month. If your system is twice the size, you might expect to use double the amount of energy, so 650kWhrs per month. Multiply that by your cost per kWhr and you should have a ballpark estimate of what heating the tank may cost you.
I'm not sure what you pay for electricity, but I'm guessing you saw a pretty solid spike in your electric bill from running that 1.5HP blower for your fluidized filter. I think that spa air pump is way overkill; all you need is a nice consistent (fluidized) roll of the media...it doesn't need to be violently boiling. I know of people running only 50LPM of air through the same filter you have with success. A 50LPM pump would only pull around 50 watts, so you would be saving about 830 watts (or 600kWhrs per month). Using the more efficient/smaller pump should pay for itself in just a few months. If you are worried about 50LPM not being enough you can get a larger model and run air to different tanks if it ends up being too much.
Another thing to keep in mind is that if you decide not to heat the air in the room, when it gets down into the 60s, you'll be pumping that cold air into the fluidized filter, which will act like a giant chiller. I noticed that when I turned off my little air pump in my tank, the heaters would come on a lot less often. That might be something to keep in mind if you are trying to keep your heating/electric costs down. Designing a filter that won't act like a giant chiller in the winter may be the smart way to go.
Hope you are taking what I write as suggestions from someone who wants you to succeed as opposed to criticism. It sounds like you have big plans in the works and designing the system to run as efficiently as possible could save you hundreds, thousands or even tens of thousands depending on how long you have the setup running. Looking forward to seeing updates on your build! =)
