Buffer is usually referred to in reference to alkalinity, or dKH
. For hard corals you want it (and calcium) high, like 8-12 dKH
. Alkalinity buffers the tank and cushions Ph swings. If you aren't swinging, or keeping a lot of SPS
corals, you probably don't need to worry about it. Some folks mistakenly use buffers to adjust for Ph, but it only works if you use the right one. Buffers based on Sodium Bicarbonate will add alkalinity and not affect Ph much, while soda ash, Sodium Carbonate, will add alkalinity and adjust Ph upwards. Older tanks use the Sodium Carbonate because it can be hard to maintain Ph in the 8.2 or better range.
Rule one: never add anything you can't test for. Guess work will kill everything. A test kit will measure all these parameters and you will be able to tell if and how much buffer you may need.
And I am a real downer...I don't recommend tangs for anything much smaller than 100 gallons. Just my opinion.