Mystery Snail Help!!

We went to get some snails yesterday and at the same time we got our water tested, our water was apparently all good and I do a weekly 40-50% water change and have never had any issues with my test at home kit.

This morning, each snail has excreted about 50 little black dots, at the first we thought eggs but then after googling, the internet seems to say unhealthy poo.

Then the snails that gave out the most black dots, started floating at the top of the tank, I moved these into a very temporary quarantine container about an hour ago and both have not shown any signs of life (with some food and water from the tank). Also around where the snail that had let the most black dots out, there was an abundance of bubbles, I was thinking this could be the snail letting ammonia out?

The other two seem to have finally woken up and now appear to be grazing.

Are these black dots normal and are the other two just sleeping? Can’t really find anything helpful online so I have started panicking slightly I understand it could just be poo but the sites online seem to say the poo doesn’t normally look like this and its a lot of excrement for something that is meant to help with tank maintenance.

Thank you

Any creature that eats vegetable matter will poop a lot. Think of cows. Algae eating snails (and fish) are no different. I have nerite snails which poop a lot, the difference is that their poop is on the tank floor not the glass, but the poop does look like your photos.