Hi, my first post here and my first citrus (one of my first potted plants).

I bought a key lime about 2 weeks ago. I fertilized it after I got it because I read that citrus is in need of quite a bit of fertilizer. I was not sure what to do about repotting so I waited a bit, but after a week I realized that the soil was never drying out so I mixed up some 5-1-1 and repotted about 2-3 days after fertilizing. When I repotted I did not add more fertilizer because most of the fertilizer (MG shake n feed all purpose, it's a 3-1-2 ratio) is water soluble, so I was worried about burning the plant. At some point, possibly about a week ago, I also sprayed with neem oil.

Yesterday (4 days after repot) I noticed some slight yellow spots on the leaves, and this morning I noticed that they are a bit worse. The top of the soil was dry, but was still moist about 1/4" down. I added fertilizer and watered, but I'm not sure if this is the cause or if there is another cause. I'm hoping I can get some guidance here. Photos below of top and bottom of some leaves. I don't see any mites crawling, but I also know that they are hard to see. Also there is a spider in my tree, not sure if I need to find him and kill him or not. If I need to check anything else or take more photos, just let me know. I just don't want to lose my tree!

Thank you in advance.