Very nice photo. I find that my pictures usually end up much yellower than it really is. I will try and use some of the methods you mentioned in your photoshop tutorial. Only problem is I only have elements, and I am not sure I can do all that stuff...
I think drawing in the top rim is a little excess, of course I only noticed this because you mentioned it elsewhere... I think it looks off to me because it seems like you should be seeing part of rim of the tank sides in the white region. This is of course nitpicking since the rest of the picture is so cool.
I think filling the tank a little more and using the actual rim with what ever colors naturally show up instead of whiting it out would be much stronger. Of course you can't do that because you already tore down the tank so I guess this advice is pointless.
I really like how the ripples eminate from the top of the Rotala green as well, looks natural.
Keep up the good work.