Q.limes have a brown tinge inside
My limes, when cut, have a brown tinge inside. The lime tree is about 5 years old in a very large pot. The tree has now rooted into the ground.

Tell me more about your lime tree. Does it look healthy? Do the exterior of the limes look unusual? When you say the limes have a brown tinge inside, are you talking about the inside of the rind or the fruit (or both)?
I am very concerned that your lime tree has rooted into the ground from its container. This means it has outgrown the container, which will put stress on the tree. When citrus trees are stressed they respond with changes in foliage and fruit. So, this could very well be what is happening here. I would recommend that you re-pot your lime tree to the next largest pot size.
For more information on growing lime trees, please visit the following link:
https://www.gardeningknowhow.com/edible/fruits/lime/lime-tree-tips-care-of-lime-trees.htm
https://www.gardeningknowhow.com/edible/fruits/lime/potted-lime-trees.htm