This has been a real bad *$#%ing day - warning pics are not good natured

[Oxymoron]

My condolences. I can imagine the frustration.
I work with H2S on a regular basis, It will have a rotten egg smell that will be very prominent. You will be able to smell this for even several days after a h2s release in very small (1 part per million is detected by the human nose) amounts.
It will also be heavier then air and will be released with agitation. If the water doesn't smell like rotten eggs at a source of agitation, ie a returm pump or power head agitating the surface, then it doesn't sound to be h2s imho. Especially if the release of h2s into the water supply was only yesterday.
Hope this helps.