How did you put the tea into the must? I'm assuming you used tea in bulk or in a teabag. Did any of the leftover tea make it into the secondary? That would be my guess as to what's floating at the top. Do you have a pic?
This is in the primary and bulk Arizona sweet tea. Having trouble with the picture but its just like the lees at the bottom. I scooped it out cleaned the airlock and put back on.
Do you stir it everyday? When it's in the primary I stir it to punch the cap that forms and to introduce oxygen for the yeast. I avoid putting an airlock on until it's in the secondary.
I use a food grade bucket for a primary and keep a lid loosly on it. The lid has a hole and I mainly keep the lid on to keep out any bugs that may try to get in. You can use a spoon to just stir it around for the first couple of days and then rack it into a secondary. Once in the secondary then put the airlock on it.