Do you have test kits? If not, start buying them.
The ZEO products are targeted more for SPS dominant systems.
The phosphate gadget you're talking about is a PhosBan Reactor. Works like a fluidized bed filter excpet it's designed to run a phosphate media. I hugely recommend running a phosphate adsorbing material. Buy one that is reddish brown, not the white kind. I would run that on your tank as soon as your tank has water running in it. It will help to minimize the initial algae bloom stages you'll go through. J&L Aquatics sells a PhosBan Reactor 150 package which includes the reactor, a pump to run it, some tubing to hook it up, and the media for $87 I think it is. You want to run phosphate media very slowly...about 150 gph through it to maxmize adsorbtion.
I think most people recommend 1/2 cup of carbon per 10 gallons, but I could be wrong there. Someone chime in!! I run about 2 tbsp per 10 gallons, and I change it out twice a month. I use the Kent carbon. If you run a large amount you change it out less often, if you run a small amount you need to change it more often. It is not good to run old carbon. Carbon will adsorb good elements from the water in minimal amounts as well as the "bad" stuff. Once carbon gets filled to capacity it will still be able to adsorb some of the good elements (they have smaller particle size), so you're only doing hard by running old carbon. Many people only run carbon for a few days every couple of weeks. If I wasn't so lazy about cleaning my AquaClear (that's what I use to run my carbon and phosphate media) then that's what I would do. HAHA! You want to run water fast through carbon, but make sure that the carbon is packed tighly so it doesn't move around and rub together rubbing off carbon dust into your tank.
Waterchanges help with water quality as well. On a new tank I would suggest 10-15% once per week siphoning off detritus during the change. Once a tank gets older it doesn't need to be done as often. My tank is a year old, and I do 15% every 3 weeks or month.
Oh, and don't overfeed!!!!!
Newbies always overfeed...
If you feed frozen food, put the amount you want to feed into a little cup or something, add RO water to it, let it melt, drain the water, add some fresh RO, drain again, then feed. Lots of crap comes out of those frozen cubes.
Oh, and be sure you have a HIGH QUALITY water source!! Where do you plan on getting your water?