I was worried about the tank being so narrow but It doesn't look bad at all.
really it takes a month to cure?
What you can do to work around a narrow tank is to shape the rock faces so they're vertical rather than horizontal or use a mixture of that. That way it doesn't take up as much room. Everywhere I read seems to say it takes about 30 days to cure (for the cement to stop leaching calcium into the water). It took right about a month for my pH to stabilize and reach acceptable levels. That being said I did my 100% water changes ever 7 days. Some people do it ever couple of days, not sure if that helps it go any faster. It's probably just one of those tests of your patience. If you want any help building one feel free to shoot me a PM.