I tried something along this line and was really unhappy about how it all turned out. I had to get a reptile heating pad to keep the tank warm, which as a drag. Then I had to top it every day, and really should have topped it off more then one each day. But the real problem was that when it came time to clean it (it was an acrylic tank) I couldn't. Anything that I put in the tank to clean the sides was large enough to cause a displacement that spilled water out of the tank.
It looked pretty for about two weeks and then it looked like crap until I took it down.
Cheers...Michael
