Okay, a few things to mention...
There's an "Aquarium Discussion" sub-forum in the actual Aquarium forum, and it's for things like this. But not only does it not get much traffic (read: hardly anyone even goes in there), such questions are totally fine here, too (and are more likely to be answered, IMHO).
Glow notices: first of all, double-check that you have the correct time zone set (My Gaia > Settings). That does throw off the timing, since the notices adjust for your local time. Second of all, remember that it's telling you your tank will begin glowing at some point during that ten minute window, not that you'll be glowing for those ten minutes. And third, you'll never see your own tank glow, only others' tanks. Thus, only other users are able to see your glow and play in your tank.
As far as people playing someone's tank, it helps to have a "glow" thread in the Aquarium forum; when your tank is glowing, users can bump your glow thread, and the users who are just browsing that forum for glowing tanks can see your thread near the top of the list. Will it work? *shrug* I've got high-yield critters in my tank, and sometimes I get players, and sometimes there's just no one playing. On that point, it's a bit random.