snail help

[Kain]

So I have a 29G Biocube that I have been running for almost a year now and a friend had it for a year before me. Now everything has been great and have not had many problems except for Aptasia that I found in my tank and I threw out that rock.

Now the reason i found it was because my filter clogged while I was out and Air bubbles were blowing out of my pump for 8 - 10 hours without me knowing about it. Since then I found my smaller snails upside down but would still twitch. Now my small ones are not twitching and i removed a few that were no longer moving or thought were maybe dead. Now my 2 big Turbo snails are turned over and like completely pushed out of their shells. They still go back inside if you touch them. I have 2 other snails that have been in the tank nearly 2 years and they are doing this as well now. It all happend with the air bubbles. I have provided pictures. The other thing that is happening now since then is this orange, brown slime with bubbles on it that is starting to grow like algea. I am constantly removing it every couple days by scraping it off and have down 4 water changes in the last 2 weeks and snails are not getting better and this stuff not going away. I am fairly new to this and hoping someone has some information for me to point me in the right direction.






Thanks in advance