You can use the Safeguard, I use it all the time as well as Valbazen. Safeguard dose is .23ml per pound of bird weight, orally, 5 days in a row. That will take care of everything except tape worm. Tape worm is much less common. You can use an inexpensive digital kitchen scale to get a weight. The most common is roundworm, and reinfection is very common. If you KNOW you are only dealing with roundworm you can do the above dose once and then again in 10 days, if you don't know for sure what worm you are dealing with, then the 5 days in a row will cover everything. If you ever need to worm for tapeworm then you'd use praziquantel which you can get in Equimax or Zimectrin Gold horse paste.
Florida has a just about perfect climate and soil conditions for parasites, it just comes with living here. Just observe your birds, watch for symptoms, worm as needed. I worm my birds every 3 months, it took awhile to work that out, if someone gets sick or is having abnormal droppings, I worm. It's pretty safe, and better than losing birds to illness caused by the parasites. I've never hurt one by worming. Make sure that you do not underdose your birds, always round fractions UP to the most measureable amount (you will not hurt them), and if you find yourself worming regularly, then try to rotate wormers. You don't have to switch every time, no point in wasting medications, but I will switch every 3 or 4 wormings.
Do not make yourself nuts trying to get rid of it in the soil. It's impossible. And even if you did, one bird flying over can poop and leave some there, and you'd have to start all over, or someone could carry it in on shoes. You would have to remove at least the top 6 inches of your soil and replace it with "sterile" soil. And even then, no guarantees. Another way to manage parasites is to rotate the ground they are on, many ranchers rotate pastures for that reason (among others). If you have lots of space, that can help. Many people simply don't have the room or resources to do that.