When installing bulkhead fittings, make sure the rubber gasket stays on the flange side of the fitting. If you install the gasket on the side with the nut and tighten down on it, the gasket will get warped and will lose its watertight seal. Additionally, there is no need to use tools to tighten the bulkhead when installed properly. Simply hand tighten the fitting and it should be fine to use. If you want a little added comfort to the installation, you can take a bulkhead wrench or some other tool to tighten the fitting just a little bit. All that is needed is a quarter turn of the nut, but nothing more.