problems with plumbing

[slimmer]

First time with a drilled tank and sump. Plumbing the sump i have a valve that is always leaking. Used parts but looks alright. I think the drip is coming from a little rectangle white part that is on the threads of the valve. Anyone know what this is for? Should i silicon it? look at the bottom threads in the pic.

 

[philfreenode]

Are you using teflon tape? You probably need to use that on the threads of your plumbing. Just don't overtighten and don't do more than 1 or 2 wraps

 

[rusland005]

Teflon/PTFE tape should do the trick, i would avoid silicon if you can

 

[slimmer]

Thanks. i used teflon and all is good. I just thought everything should be sealed with the o-rings.Still not sure what the little white plastic piece is for?