Any biology students here? YVR

[Animal-Chin]

Have you tested your arm with new water that hasn't been in a tank? I'd do that first and if you do get the rash its from the saltwater mix, if you don't its from something else. Then I'd take some sand from the tank and just lay it on my arm for 15 mins, does that make the rash? If so, why do you react to sand? Oh or is it a temp thing, if you cool the water do you get the rash?

How are you not conducting your on experiments? lol