So, I'm looking at this DIY guide on building a concrete aquarium backdrop. I'm trying to find a building method for constructing the underlying landscape for my indoor water garden project, first mentioned here, also here.
What I'm hoping is that I could use the above method, but with something heavier like cinder blocks for the base. I believe that I can get away with less detail on the form, because most of it will be covered in media or loose rock. I am, however, worried about cracking and leakage, as I won't be around regularly to maintain it (probably two visits a year tops.) I've heard of something called Herco's Neoprene Pond Coating, which sounds appealing. It's apparently some sort of paint-on sealant, and also works as a crack-filler. I found it on this koi pond forum, along with mention of the Quikrete Quikwall stuff from the DIY plan. Does anyone know how this compares to, say, the 9:3:1 sand/portland concrete/lime mix advocated by one of the pond forumers? My experience with concrete doesn't go much beyond setting fenceposts with premade mixes. Any help or suggestions would be great.