I'm not sure where else to place this, but I'll try here.

I'm going through my first cycling, and am currently going through my fourth week, almost fifth week of waiting for my tank to cycle through. I have three danios (leopard) helping me cycle, along with four decently sized plants, a small java fern, and a huge floater sort of plant (can't remember the name off the top of my head. ><). My tank is currently in the kind of hazy area, and I am waiting for my bacteria to grow in. I try and only give the plants 8 hours of light so that they bacteria has more time to grow. I'm human, though, and sometimes forget to turn off the light. :(
Along with the entrance of my now biggest floater and two of my medium sized plants, I had a huge snail and apparently a small myraid of snails introduced to my tank. At first, I was irritated to have such a huge number of pests brought into my tank. This cleared after they ate away the alge, so I don't mind them so much any longer. :D

Lately, though, I have had a few of my bigger snails (they have all grown rather quickly) so float around the tank. I was afraid at first that they were dead, but after a while they usually tend to sink and go back to crawling around on the gravel/rocks/plants.
Here comes my question:
Is this normal??? And, can anyone give me any clues as to why this is happening? I don't dislike them as much as I did before, and wouldn't mind keeping the biggest snail I have, as he's at killing off my algae.