So here's something interesting.
In the past, the BT attachment had worked pretty well for me. Occasional "Port in use" errors, but that's it. Recently, it became pretty much unusable. It would either be a port in use error, or it would time out while trying to upload.
The fix? I moved my computer's BT adapter closer to the tank using a USB repeater cable. Now it works perfectly. I haven't even seen any port in use errors (unexpected benefit).
My theory is that the port in use errors are a sign of iffy signal strength and the RF noise in the house finally got to the point to where it interfered too much making the intermittent problems constant. Moving the computer's BT adapter away from the computer and a little closer to the tank seems to have solved everything.
Here's the cable I'm using. It's longer than I needed, but it's cheap.
http://www.amazon.com/gp/product/B00HYJ ... UTF8&psc=1
--Colin