[Sebsantoro]

Hi guys, so i have a 20gallon IM fusion nano tank with a AI prime light set to 80%uv and all other colour between 60-75% for about 8hours a day. My uv sterilizer is always on and my heater is always set at 78. I have 2 clown fish with a anemone, a yellow tang, 2 peppermint shrimp, a trigger shrimp, a diamond goby, 2 soft corals and 3 other corals that i do not no what they are exactly. Resently my corals have not been opening up like they used to amd i do not know what is wrong. My salinity is at 1.025 exact and my tests came out good. Alkalinity= 2.28 , phosphate=0, nitrate=0 and calcium is at 450......i went to the closest fish store and clerk made me replace my rowa. I did a 20% water change avout 4 days ago and still no corals open....fish are doing great and eating well.......any advice on what i can adjust or do to help corals open up again and grow.