Tony, actually I don't use seiryu stone in my tanks with shrimp, as they do raise the pH and hardness of water. The rocks you saw were plain granite, which are perfectly fine for shrimp and don't look that bad. If you do use seiryu stone, make sure to monitor your pH, gH and kH, because it can mess your params up.
I have an Ebi as well and I noticed you have seiryu stone's in your tank. I plan on getting some crs as well, how have they done? since i've heard they like low ph water and that the seiryu stone raises ph and hardness. Thanks for the help. Tony