Did you use l-citrulline or citrulline malate? If it was l-citrulline that is a good dose so no surprises the pumps were insane. 6g is the clinical dose of cm and should work great as well. It's a great supplement and has health benefits too.
Huge pumps are more a function of larger than normal blood volume IMO and have less to do with improved blood flow. Steroids, gh, insulin, all these drugs which make you bloat a lot = skin splitting pumps. Amino acid NO-boosters = slightly better vascularity. All these fellas in the gym who never touched drugs drinking PWOs talking about their supposed "sick pumps" because
they read about it in the ads and on instagram... and I'm like, "bro, you don't know what a fucking sick pump is". A sick pumps comes from test, anadrol, gh and insulin.
I've actually asked a lot of guys what they notice from their NO-boosters, do they really get more pumped? More often than not they say, "I think so".
Personally I've used enormous dosages of citrulline, arginine, agmatine, etc and if I'm honest I can't say they give any extra pumps whatsoever. Slightly more veinage. Now a steroid pump is very distinct.
I just started taking cittruline malate about 6 months ago. First as a stand alone, then in a combo pre workout. 6g pre. It's not so much the pump I notice as I do the leg it added to my workouts. For sure can workout longer and harder with less fatigue than before