Your tank looks nice. I wish my first tank looked that good.
Carbonate buffers? adjusting the pH? I thought you were still worrying about algae and initial equipment?
Right into the deep end of the pool eh?
Superbuffer DKH is just soda ash. (Is just carbonate alkalinity buffer). Personally, I go the local Leslies Pool Supply and buy a gallon bucket of Soda Ash (Superbuffer dKH) and Hardness Up (Turbo Calcium). Ten bucks a pop and its identical to the stuff you get at the LFS. Been using it since before I set up any of my existing tanks.
The use of carbonate buffer to raise the pH value of your tank is the wrong way to approach this issue. Instead, start looking to get your calcium and dKH values where you want them by testing for their concentrations and slowly adding a little of each on alternate days.
First get your levels where you want them (420ppm calcium and @10dKH). Then worry about your pH.
The correct levels of calcium and alkaline buffer (dKH) should keep your pH at tolerable levels.
Here is a link to all the chemistry articles from RK magazine. Its a ton of very useful information. And the articles are broken down by subject. About the third time you read each one, it really sinks in and starts tying into the other articles.
http://reefkeeping.com/issues/subject/chemistry.php
Warning! The deep end is really deep! I recommend SCUBA gear!