You may also find the tips in our balanced diet guide, which takes in the various pros and cons of things and helps you strike a long term balance, and the information in our low calcium diet list helpful.
Recommendations For A Balanced General Guinea Pig Diet
Low Calcium Diet For Bladder Piggies
Please be aware that powdery calcium is a normal way of the body to excrete excess calcium and not harmful in itself. Unless you have acute problems with chronic/recurring urinary tract issues, you will have to aim at a balance; cutting out all calcium in a diet comes with its own issues for the long term. Don't err too far to the other side without need!
For instance, magnesium is only found in high calcium veg; it is not added to pellets, but it is important for guinea pig long term health. Everything in moderation is still the best guideline for healthy guinea pigs!
You also need to count in the calcium in your water and in the pellets, high calcium is not just due to veg!