Raising pH in fish tank for spirulina algae?

"If you want to go the chemical way, the safe approach is to alter your pH by changing your kH. Instead of buying products like "minus-ph solution" or "plus-ph solution" (note: those mentioned are fictatious produces cos I dont wanna offend any brands) that are acid or alkaline solutions, look instead for KH buffer powder. When you get the KH powder, there should be an equilibrium pH value on the label. Look for an equilibrium pH value that you are aiming at."