That looks like salt damage to the leaves in the second picture, aka fertilizer burn. I would lay off the foliar fertilizing/fertilizing in general until your tree recuperates. Flush the soil with water until it drains freely from the bottom and runs clear, you need to wash the accumulated salts out of the soil.

I think it probably is also fertilizer burn. I would look at the N source in your fertilizer. If is is mostly from urea, this is not a good choice for container citrus. I would switch to Osmocote Plus and Dyna Gro Foliage Pro. Also, I would actually check how much water has accumulated at the bottom of the pot. You say you are checking moisture at the "root level", but if that tree's container has turned into a bath tub, and your moisture meter isn't checking all the way down, you're also dealing with root rot. Get a stick and push it down to the bottom of your container and see how wet it is down there. You say you added pine bark to the soil - how did you do that? Did you pull the tree out and completely change all the potting medium? If you just added it to the top, that won't help drainage. Pretty sure we're looking at two things - too wet and too much biuret build up from your fertilizer.

Patty S.

Yes, I did pull out the tree to add pine bark to all of the potting medium. The stick in the pics is a wooden dowel I keep in the container to check the moisture at the bottom of the pot. Thanks for the advice. I will definitely flush the container and make the switch to the recommended products after the tree recovers. Thanks again for your help. Hopefully, with your suggestions, I can nurse my tree back to optimal health.