I have had some chaeto in my intank media rack for a week or so now. I have the underwater light on for 10 hrs a day with my normal daylight cycle. The chaeto still appears green but how can I really tell if its doing well or not?

its still there and its not shrinking in size breaking and its still green, if its light green almost transparent its not getting enough light

If it is green it is alive and if it grows it is doing well.

If it's putting off bubbles.

In the freshwater planted tank niche they call this "pearling" and it is a great sign that your chaeto is making large amounts of oxygen. This in turn pretty much assures you that your cheato is in overdrive mode.

Not to hijack the thread but I have another question~is the chaeto supposed to be completely submerged?
I'm having major issues with my new media rack and water flow~flow sucks.

might check out this thread. he made a bigger media rack that allows for greater flow. and cool pic of it also.

http://www.nano-reef.com/forums/index.php?showtopic=225458