bulkhead fitting leaking

[tableforglasses]

I have a bulkhead fitting that is leaking on one of my drilled corners. It is not bad, but a steady drip. I have checked the fitting bolt and it is tight, and yet some how it is still managing to leak. It is not the pvc pipe the leak is coming at the base of the tank. There are no apparent cracks in the fitting. Any ideas how I can stop this leak, I am just not sure what to do.
thanks

 

[zanclus]

The only true way to stop the leak is to remove the bulkhead and either reset it, using a new gasket or replacinging it entirly. I personally use a thin layer of silicone around the flange end of all of my bulkheads and they have never leaked when I have.