Hey all brief question, what is it? Half dies off at night and back in light, chemiclean didn’t get it but drove skimmer nuts. Nitrates at 12 ( high) phos at 0 all other parameters great according to Hanna and apex. Tank is 150 with 56 gallon sump, running UV as well ( flow not tested getting inline flow meter atm) tank is 7 months old and sps and lps growing great! Thoughts?