Big change. I was surfing the net as usual this morning and found Ames' Blue Max tank coating. I'm going to play guinea pig and try this out on my tank. This stuff could make building big tanks much easier. One big plus over pond armor that I see is that you have much more time to work with it before it sets.
Check out this video of this new product. I'm going to use it on my 3600 gallon tank.
http://www.amesresearch.com/video/bluemax.wmv
http://www.amespaint.com/detail.aspx?ID=50
http://www.amesresearch.com/bluemax.htm
Really interesting product and demo. It says the product is safe for cisterns etc. but I still didn't see any explicit statements/claims re: safety for the water supply (chemical leaching etc). I may have missed it at the website; if it is safe for the fish then this seems to be an awesome solution!