When preparing a floor for a coating, the process will usually involve an muriatic acid wash. However, the surface must be neutralized before applying any type of coatings. We use 10 parts water to one part household ammonia. Rinse the garage floor thoroughly, and broom it real heavily to get all the residual acid off. I like to use a commercial floor scrubber with a white pad. It works so much more efficiently. You can rent a scrubber from the home improvement store. About $25 for a day, it’s well worth the rental price – especially if you have a large garage.
The key to that is once it’s neutralized & rinsed off, rinse it off a second time. Then take a pH Pool Test Strip and put it down in the wet concrete with the pad side down. Look at the pH and make sure that pH is in the 7 range. If you don’t get that acid off and you put on your top coat then it won’t bond and it’ll fail. You don’t want it to be too alkaline either. The expansion joints is where the muriatic acid will tend to settle, so be sure those areas have more attention in the cleaning process.