Hi there
I presume you are talking about two different T's that are not in the same enclosure hey?
But are they in the same room with the same type of mold?
I would say do some investigation in the room or if a bathroom is adjacent, investigate that.
Look at the "trap" (the black rubber under the sink or loo) and see if there is any mold on that. It might not be white but a blackish brow with small white spots.
If not that, but another let me know.
I think I know what this is, as I've seen it before (though not on a T) but I need to make sure for you.
If you are able to get off any samples of the T, and you have the following available do as I instruct please.
Method 1:
Put about 5mm x 5mm (aprox 3g - 5g) on under a normal microscope. Get a picture of it as it is with a 4x zoom and 8x zoom. Then put some alcohol on it (vodka works well, cheap is fine (40% or higher)) and then wait 2 - 3 min. Then take a pic at 4x and 8x again.
Method 2:
Take a plastic lid (panado 20x pill cap size, something that can be "eaten" by alcohol). Put as much mold in the container as possible, keeping it level and not to let it "overflow" beyond the height of the cap. Get yourself something like Captain Morgan Spice Gold. Fill the cap till it just just overflows, then leave it for 5min. The alcohol should be almost gone once you return, put in again to just just overflow. Do this about 10 times total.
Once done, take a pic and send it to me. The alch should eat the mold away if your lucky, if not, it's a strange kind of mold.
I'll post more once I find something regarding T's.