Tank Wide Bacterial Infection

[NorthEastFisherman]

After having 5 galaxy rasboras, 3 neon tetras,1 julii cory catifsh, and soon to be 1 bolivian ram die from what i thought was too high of a pH i went to my lfs to figure this out. After doing water tests and putting all the pieces together. Me and the guy there found out that the sand i got from a local river was infected with a bacterial disease. I got sand from a lake before and nothing happened so i didnt think it would happen from the river. My dad and my theory is the sand from the river is actually silt that came from runoff sand and such used to remove ice on the roads. When the ice and snow melted it went down to the river where i picked it up. Even though i cleaned it i guess i didn't clean it enough. So i bought this new bacterial medicine that the man in the fish department said worked really well when he had this issue. Im treating the 29g right now as we speak but im wondering have any of you had this problem? And if so how did you treat it. My inhabitiants as of right now are, a gold gourami, rainbow shark, 3 julii corydoras, 5 glowlight tetra, 2 neon tetra, and 2 bolivian rams. The ones showing the signs of distress is the female bolivian, and 1 julii. The bolivians eye looks white and puffy and it looks like it has a spinal issue, and the cory is anti-social, hiding behind the thickest plants not coming out to play with the others.