Found this helpful:

"Nutrition and Skeletal Health in Dogs – Relationship of Nutrition to Developmental Skeletal Disease in Young Dogs" by Daniel C. Richardson Phillip W. Toll
http://www.joint-health-for-dogs.com/nutrition-dogs.html

Summary:
http://www.dogster.com/forums/Food_and_Nutrition/thread/663911

That's what I bought, Innova Large Breed Puppy, with 0.9% Ca:
http://www.dogfoodanalysis.com/dog_food_reviews/showproduct.php?product=2281&cat=all

Authors' credentials:
http://www.k-state.edu/media/mediaguide/bios/drichardsonbio.html
Veterinarian and nutrition specialist, his career mostly at Hill's Science Diet (hm). That is also where the co-author is acc. to his publications in veterinary journals.

I have fed Wellness a couple times. Or attempted to feed it. I've decided there is something that doesn't agree with GSD tummies in it. Or at least something that the GSD's that come through my house. I tried to give it to 2 fosters and Medo. All had the runs on it. Booo!

Wellness didn't work for Halo either. She did fabulous on Orijen LBP - figures, since it's so expensive!

I've tried the Wellness Core for my adult dogs and while they didn't get the runs, they had room clearing gas on it.

I may have used the one of the other Wellness formulas for Caleb when he was a puppy and he was generally OK on it.

(Isn't this helpful, Sarah - telling you things that didn't work? )

Johanna - Dante had room clearing gas on Wellness Core as well, I finally decided it was the 'taters

I've used other grain free kibbles that have 'taters in them without a problem. For my guys, I was suspecting flaxseed. If I stay away from that in the food, they don't have a problem.

I changed Riva's food again. She has been on Canidae Beef and Fish but has been itchy lately. I had planned on putting her on grain-free in a few months, but decided to do it now, in case it is allergies. She'll be 1 yo in a few weeks. (Although the itchies could be from dryness in the house since we've started the heat recently) Started the switch over to Wellness Core a few days ago. The calcium and phosphorous are not bad at all for grain-free. And do I still need to be concerned about that since she seems to have stopped growing, or if she still is, it's not very apparent.

Now I see the posts about Wellness Core and gas. So far no problems and no change in poop or anything else.

Hope the Wellness Core continues to agree with Riva.