If you are adding larger amounts of acid for such things as lowering TA or with borax to achieve 50 ppm borates then you can add the acid in larger quantities. I usually recommend adding no more than a quart at a time in a 5 gal bucket of pool water per 10000 gallons. Give a quick brush down your pool walls in between additions. This creates currents that 'stir' the water in your pool. You can add the next batch of acid right after brushing.
If you are just adjusting pH I would not add more than a pint at a time per 10000 gallons.
If you have done an acid demand test and KNOW about how much acid you need to add to achieve a certain results then go ahead and add it all at once (but if it's over a quart per 10000 gallons I would add it as above if it were MY pool. This will help prevent any localized areas of very low pH, which can damage pool surfaces.
If you are just adjusting pH I would not add more than a pint at a time per 10000 gallons.
If you have done an acid demand test and KNOW about how much acid you need to add to achieve a certain results then go ahead and add it all at once (but if it's over a quart per 10000 gallons I would add it as above if it were MY pool. This will help prevent any localized areas of very low pH, which can damage pool surfaces.