Anti siphon valve……

[charlie_the_tuna]

Ok, I got it out. The valve I took out seems to be in decent condition but as it’s out and most likely 30 years old, I’ll replace it for $12 bucks.
So when I replace the 90 degree fitting into the tank and the valve into the fitting, should I use Teflon tape? Teflon paste? What sealer, if any should I use?
I couldn’t identify what was on there. It was old and crusty.
Also, west marine gets $9.29 per foot for new fuel line. I see marine grade line on eBay for $3-$5 bucks a foot. Should I splurge and get the $$$ stuff, or is it all pretty much the same??