Water leak from Holding Tank Drain

[gwilliam]

Have just filled my tank with the disinfecting solution prescribed by Airstream and now have a drip from the drain.

I removed the inspection cover and confirmed the drain plug is leaking and my first question is does anyone know the size of the hex wrench required to fit the drain plug?

I followed the Airstream procedure which is 1/4 cup of bleach per gallon of water and use 1 gallon of this solution for each 15 gallon of tank capactity. Wouldn't have thought a 5-6% bleach solution would disturb the seal to cause a leak. No problems before but the tank had been sitting empty for a while. Is it possible that is detremental and could result in a leak if sitting around in 90deg plus temperature, although we haven't had that many of those days this year yet.

I would be interested in any insight available.

thanks