How and when to grow Pink Grapefruit

Hi, my beautiful 7 year Pink Grapefruit tree all of a sudden just died on me. It’s leaves shriveled up, turned brown, then the whole tree collapsed. Prior to this, it was perfect – gorgeous to look at (many neighbours commented on it, particularly when it was full of huge orange/pink fruit against the bright green leaves) and was very productive, fruitwise. Prior to it dying, I fertilised it, around the dripline. Next to it is a Meyer lemon tree and a mandarin tree, both doing well and have all been treated the same. They are in a sunny but sheltered position, South-west facing.
I would like to plant a replacement Pink grapefruit tree. When is the best time please and what variety is best?
Many thanks, Sarah