From what I know that around 0.9 to 1.5% is a general target most prefer for a puppy.
Have to take into account calories too because you are more concerned about total calcium
AAFCO says an ALS food cannot have more than 2.5% so they consier 2.5% to be safe for puppy
Though most of us would choose to go lower.
The studies on Great Dane Puppies said no more than 3%
NAPWDA Certified Cadaver Dog
Waiting at the Bridge (italics
=GSDs) (hemangiosarcoma=blue):Grim , Cyra, Toby
, Rainbow, Linus, Oscar
, Arlo & Waggles