Hi everyone, I have a 1 year old reef tank. It is 100 gallons, plus a 25 gallon sump. It has a magus curve 7 skimmer, 2 Ai sol lights from 9 am to 8 pm 14 inches awl. I have two wp25 that push a lot of water plus my return. I have only lps corals. My parameters are stable salinity is 1.026 p04 is near zero so is no3. I have a tlf reactor with biopellets that I just started. I have a uv sterilizer as well. All new bulbs and everything works fine. I sometimes put kalk in my ato. Now to the problem... I'm thinking it's diatoms on my sand bed that will not go away no matter how hard I try. I do weekly water changes etc.. I feed every other day either pellets or fresh food that I made. I two tangs, wrasse, 2 clowns, Niger trigger, and 2 chromis. I have cheatomorpha and dragons breath in sump. My sand is the caribsea a rag alive. Please help me get rid of this.... p.s I do have egg crate below the sandbed..