What's best to use for AN and NPT threads?

I found pipe tape in the N20 filter, so I don't want to use that.

Looks like some connectors come with a red color paste already on them. Is that red Loctite?

 

When I bought my NX kit, it came with red sealant, Im not sure if it was red Loctite. I have used teflon paste before and it seems to work just fine. For AN threads, I dont think you need it because the fitting does not seal with the threads.

 

Don't use anything on AN fittings, they have a tapered cone that provides the seal, its not the threads, they just force the seal together. Do not overtighten, it doesn't take much. For NPT teflon paste or thread sealant. Some nitrous companies supply a red thread sealant hence the red stuff you see, its not loctite.

 

Auuugh...learn something new today...THANKS.