I decided last night to give this tank a thorough cleaning. I removed ALL the substrate, gave the tank several freshwater rinses, treated a few spots with an excel bath, and replaced the substrate, using flourite black in the back and carib sea crystal river sand in the front. I wish I had done this 6 months ago, the reflected light is so nice, and really illuminates my 2 remaining Danios. (one got caught in the filter just last week)
I am considering selling this tank to make room for future projects. It's one of my favorite things I've ever made, but it's very small, and I'd like something very large now. If you're seriously interested in a small tank like this, let me know! I may bring it to MsJinxkd's party in april... still contemplating.
I just snapped this pic with my phone, so sorry it's not super... but you can really see the difference the sand makes.