My tank is 20 gallons; excuse the remaining dirtiness of the tank and the table it's on, currently just keeping the tank on a table while I finish cleaning it it up, and I put the rocks in the tank temporarily to gauge how well they fit. The final tank will have a substrate of 1mm aragonite; is this too little rock, or should it be okay, and does the scape itself look effective? I plan on very modestly stocking the tank; just a fire goby, some hardy corals like GSP, and possibly a cleaner shrimp. Any advice would be appreciated