Under normal circumstances the issue pond builders are faced with in regards to concrete is how to make it smoother. However there are times when the surface is so smooth that there is not a lot of surface tension for a coating to hang on by and it will be necessary to make smooth concrete rough.
One of the most recognizable scenarios for smooth concrete is a water slide for a pool. Generally, these concrete surfaces are polished smooth enough to resemble nice polished stone work. When they are coated, the epoxy will have nothing to grab hold of and can eventually peel.
Most people think that the easiest way to make smooth concrete rough is by acid etching it with muriatic acid. The problem is that muriatic acid is not eating away at the concrete to make it rougher, but eating away at the calcium within the surface of the concrete. When that calcium is dissolved, the concrete will then have the appearance of having been roughed up. The problem is that the concrete did not actually become rougher. Instead the surface pores of the concrete have become clean, thereby making the concrete surface appear to have changed.
So when it comes to a polished concrete surface, the rock, sand, lime and cement have been polished so smooth that there really are not any surface pores to be exposed. Because of this acid etching a surface like that will not really accomplish t task of making smooth concrete rough.
There are only two ways to get a concrete surface to become rougher. This is accomplished either by grinding with a very coarse but flexible disk, or by sandblasting with a very aggressive media that is used to blast the surface. Once the task is completed, then the surface can be etched with muriatic acid. It is important to not forget this step as the grinding or sandblasting will expose new calcium that will also need to be cleaned off prior to coating.