Folks, if you've recently upgraded or renewed your annual club membership but it's still not active, please reach out to the BOD or a moderator. The PayPal system has a slight bug which it doesn't allow it to activate the account on it's own.
The T6 bulb was made to fit a standard T12/T8 fixture but at the T5 efficiency. I haven't seen many T6 bulbs for this hobby. But if you are looking to get a new fixture. Just go with the T5.