Im most definitely taking my tank seriously and want the best for it. Even though im pretty new to the hobby and my tank been 4 months old i try to keep everything in check, but like i said i am new and most definitely not know much about all the bad stuffHmm. LFS aren’t always the best at giving advice. If I were you (you seem to be a serious reefer) I would get a basic microscope from Amazon and ID what you have.
You’re going to need it occasionally if you stay in the hobby. Depending on what it is, you will want to stop water changes, trace element dosing, etc.
Now you might be fighting blind folded.