I have an 8-bulb t-5 unit. The last socket and the third to last socket are having problems. The last bulb was blinking, the third to last was not lighting at all. The bulbs are 6 months old. I figured it was the switch which both of these are wired to, so I moved the bulbs and they are now both lit. So my question is, what is wrong? Do you think its a bad ballast? The other 2 sockets in the switch are fine, but I'm worried if they go off I won't have enough light. I only run 6 out of the 8, so so far it isn't a big deal.