PH Difficult to control

[waterbear]

Actually, this sounds pretty normal for new plaster and a SWG. Once your plaster has fully cured it should get a bit better.

[Jeffski]

How often will I need to add acid to my new pool with SWCG? Roughly.

[Poolsean]

It's really all going to depend on what type of surface you have and the quality of the water.
If you have a plaster pool, there's a tendency for the pH to increase almost every day, until the plaster cures. This may take a few months to a year. Again, depending on how much your pH rises, will dictate how much acid you need.
If you have a fiberglass or vinyl pool, the pH rises less and you will have less acid consumption.

Above all, keep your pH in check so that you don't have additional problems down the road.