if you have the greatest supa dupa uv flouro tube and have it more than 25cm form where your reptile is it does not matter how much calcium supplement you feed it, it will not be able to metabolise it.
u.v tube needs to be close, even then sunshine, just a few hours a week is best.
latest theories suggest that no reptiles need uv lighting, but i did have spasming issues when not using tubes, so in my opinion beardies do better with them.