Has it been in the same pot all 3 years? If so, it probably needs to go into a larger pot or into the ground.

No, each year as its gotten bigger I have increased the pot size 2x's up. That is its third pot, the next one will be the fourth

So what type of soil should I use under the current conditions? I was told that I might want to take the tree and get rid of all the soil, wash the roots in bleach water, then replant the tree in the native FL soil... Will this kill the tree?

Hi Bryce.
It's untrue your lemon didn't bloom in NJ because of lack of sun. That is unless you grew it in a dark corner instead of a sunny window, and if possible, outdoors in summer.
Citrus sold at airport stands are non-grafted..they're seeded plants. Seeded plants take several yrs before flowering/fruiting..as long as 7-14 years.

Yellowing can occur for different reasons. It's possible the change of environment stressed the plant, which caused yellow leaves.
It's always a good idea to check for pests..(Mites, scale, mealy, etc)

You asked about soil for repotting..use a well-draining soil with additional Perlite.

I would NOT rid all the soil from the roots then add bleach to top if off..You asked if it'd kill the tree? I'd say it sure won't help.
When you mentioned replanting in FL soil, do you mean transplanting the lemon in the ground? If you're talking about potting in a container, I'd use fresh soil, (not soil from your garden) For one, it's not sterile..you'll have to deal with weeds and possibly bugs. I'd instead buy a good soil, if possible, used for citrus..Living in FL, you should be able to find an appropriate soil..if not mix your own.
Also, fertilizing lemons are no different than feeding any other citrus.
My citrus fertilizers are 10-4-10 and 12-6-8
Nitrogen, (first number) should be higher.
Is your lemon in the house or outside? Toni

The tree is currently sitting on a stand in the backyard getting about 95% sun coverage throughout the day.

I looked very closely for bugs or pests and it seems to be free of anything. The pictures at the begining show the leaves in high res and I took about 20 more and examined them closely, both top and bottom of leaves.

When referring to using Florida soil I was going to take a shovel and just get stuff from the ground. I did not think about the weeds, bugs, etc.

When I mix my soil in the larger pot what ratio of perlite should I use? someone also mentioned builders sand works as well..?

Hi Bryce..
First I want to say, you're so lucky moving to Fl..congrats..
Okay, no pests, so I'm 'assuming' the move had something to do with yellowing leaves..You know how plants need adapting from location A to location B?
I'd remove badly yellowed leaves for a couple reasons..The first is appearance. Secondly, (some ppl may disagree) but I feel there's no reason keeping discolored foliage on a plant due to energy will try reviving those leaves, (it won't happen) You want energy directed towards healthy and new leaves..That's just my opinion...
Anytime one uses soil from the ground, they're bound to have problems such as weeds and pests..Of course this is up to you, but I wouldn't do it..That's the reason we pay so much more for sterilized, 'dirt.' LOL.
I too use Builder's Sand, but some ppl here on GW are against it..Bryce, I've been using sand over 20 yrs w/o problems..My mix consists of all purpose soil, Perlite, Builder's Sand, (do not use beach sand) and a handful of peat..Peat isn't mandatory, but it's something I throw in.
Did u ever mix your own soil or use strickly from a pre-packaged bag?
The problem is I don't measure..I've been doing it so long, I toss this and that in a container, mix and plant..Let's see, I'll give u an example..8 cups of all purpose soil, 2-3 cups of sand, 2 cups of Perlite and a couple handfuls of Peat. Mix thoroughly, then pot up..Add a bit of soil on bottom of new pot, slide in citrus, then fill the remaining pot w/mixed soil..Since my citrus are grafted, I do not cover graft..Give a hearty drink of water until water seeps out of drainage holes..Does your pots have drainage holes? It's important they do; you don't want a plant sitting in water.
Is your lemon root bound? Does it need potting now? Don't overpot, though living in Fl, you might be able to get away with it...Hopefully your lemon will grow faster than it did living in a cold climate.
BTW, I don't know how determined you are, lol, but if you really want to use garden soil, you can always bake it..but let me warn you, it STINKS..I've done it before as an experiment. I believe baking is 350 for 45 mins..Honestly, it's not worth it..and like I said, your house will smell..LOL. I did it w/bagged soil for indoor use...the reason I baked it was while repotting I found weed seed and bugs in the soil..this was several yrs back..Never again..
Good luck, Bryce.. Give your lemon time to adapt. Water well, but don't keep soil soggy..Let it dry a bit before adding more water.
Since your tree is outside, hose foliage..They love it. It keeps leaves clean for one thing, and helps raise humidity, especially if plants are grouped together. Good luck, Toni

Well My tree is actually doing worse since I repotted it.. I got a soil Kit at home depot and here are the results.
PH - 7.5
Nitrogen-very low
Phosphorous very low
Potash - very low

I took this soil from the original rootball. I planted the tree in a pot about over twice the size with Mircale grow tree and shrub soil, as well as added in about 1/4 perculite.

I only got one kit but i assume the dirt is okay around the new dirt area. On a side note the tree has lots of new growth, but the old leaves are yellowing and now many are turning brown and brittle from the sides of the leaves inwards..

Help if anyone can...

Bryce, the Ph is way too high..
What is Perculite?
I'd have thought twice about potting in a container twice the previous pot size.
For your sake, I hope the roots grow into its new home..but it's going to take time.
I think the main thing you should focus on is lowering the pH. Other than that I'd let the tree be. Plants don't like being moved around, numerous chemicals.
Check this site for pH. It may be of help.
http://en.wikipedia.org/wiki/Soil_ph Scroll down to Altering soil pH.
IMO, once you lower pH, your tree should do fine. Brown and yellow foliage will be replaced with new, so you might as well remove all dead and dying leaves. Toni