My photography has been mostly put on hold recently for a new project that's been taking up all my free time. I just built a bowfront stand/canopy for a 46 gallon bowfront tank and started building a saltwater reef setup. I never built anything "real" before so it was an interesting challenge. Anyway, I was trying to take a pic of a tiny snail and I was having trouble getting my macro lens to manually focus! The odd thing is that if trying to take the shot at an angle (like a 45 degree angle from above), I couldn't focus through the glass... even manually. But if I was pretty much level with the snail, I could focus fine. Don't know if it has to do with my bowfront glass or what, but my own eyes can focus fine... why can't I get a camera lens to manually focus? Didn't even bother trying auto focus. I'm stumped!

Or maybe I was high... i dunno.

This was two days ago and I haven't had a chance to play with it again.
Also, any other tips for taking macro shots of corals, fish, etc would be helpful. Everything is constantly moving. Lighting is challenging too. Shooting thru glass doesn't help either.
btw, here's a gallery of my build process if it helps to understand what I'm talking about or you're just plain interested.
http://d2creative.smugmug.com/gallery/6218728_hLpFH
Thanks!