You can get commercial
alk buffers from the
LFS. Seachem and Kent I know make good products, but you can save yourself a bunch of time and money by going to the grocery store and buying a box of Arm & Hammer baking soda. Works just fine as a buffer.
The big 3 you're going to want to keep in check are calcium, magnesium and alkalinity. All 3 are inter-related and important that they stay withing specific ranges.
You can use this very handy calculator to figure out how much of what to add to bring your levels in line.
Reef Chemistry Calculator
