I grow citrus in the ground and in pots. The photos tapla provided are not photos of citrus tree roots. Citrus roots are fibery and dense. When you get it out of the pot, a gentle shake might dislodge most of the soil. I borrowed this photo from the internet - this is an extreme example of what the roots of a potted citrus look like. Your tree is small, I doubt it has this many roots.
https://www.google.com/search?...
Citrus like a soil pH of 6 -7. Read the article below:
https://fairchildgarden.org/sc....
Without acidifier, iron and citrus specific nutrients, your tree will develop a permanent case of chlorosis.
