I've used Reef Crystals before. It's a good salt.
There is a place for dosing a "buffer". When Alkalinity of the aquarium is low then it's appropriate to dose an Alkalinity additive ("buffer"). "Buffer" is a marketing term and it's really misleading. It is not appropriate to dose anything just to alter PH.
The problem with a very high Alkalinity is that it increases the chance for Calcium carbonate precipitation. When this happens your Calcium level will drop and cannot be raised, Magnesium drops, anything above the ambient water temp will become encrusted with calcium carbonate like the spindle of a water pump, the magnet on a powerhead, heaters, etc. This can damage the equipment.
Ironically, the Calcium carbonate precipitation caused by excess alkalinity can also lower PH.