I just added a small diamond goby to my 15g with a 2" Fiji pink sand bed. I run a nutrient rich tank with pellet, frozen, reef roids and phyto. My nitrates and phos stay at .5 nitrate and .025 phos. By Fluval test kits. Since adding the goby I've noticed him hitting the edge of rocks and digging up some grunge. And my phosphate has hit 1.0. Should I be concerned? Everything looks fantastic. Would his digging have caused a momentary spike? I just did a 3 gal water change on weds and everything else it spot on. Just the elevated phos.