I also get mine from starloc in the largest bottle they do,
and at the same time buy some smaller dispensing empty bottles into which I then decant some CA for the shed and keep the large bottles in the fridge.
That way the large bottles will keep completely fresh for several years, or at least until they are used up.
If the smaller dispensing bottles go off, (may be warmer in the W/shop)
It's not a great loss.
John. B