I love diamond gobies. Best sand sifters IMO. Ive have three jump out though, last one was in the tank for two years and jumped. I refuse to cover the top of the tank though. Good luck, that sand will be good
It will do fine. I have special grade as well. They keep the sand clean in the entire tank. Even in the low flow area my sand bed is clean. It will move sand around a lot, you want to make sure your rock work is stable.