I would not buy it until you need it, there are many, many suppliers in florida.
Down here where I am, in a month or less the bleach is getting weak and have to compensate for cleaning roofs.
Not worth it to buy it more than a week or less ahead of time.
If I had more than 1 supplier then I would buy it the day before or the day of the job. Since I don't have more than 1 supplier, I have to make sure that they have it or I have to wait 1-5 days for it to get here.