Acid blends always have a weird smell to them. I wouldnt describe it as rotten eggs but if you said it smelled kinda sulphury I'd agree

I always smell fish.

Caustic smells like fish to me

What kind of acid were you using. What was your titration?

You’re probably just smelling it from your base water. Does your ground water have a lot of h2s?

Tanks come pre-infected with pectinatus?