need help

I have had a reef tank for about 6 years now never had an issues with coral growth etc but ive never been able to get the crystal clear water look and im trying to find out why. my water params are Alkalinity-9 dKH

Calcium-500 ppm

pH-8.2

Ammonia-0

Nitrite-0

Phosphate-0

i have a 180 gallon tank with over 200 lbs live rock live sand a 50 gallon sump with reef octopus protein skimmer i dose once a week with zooplankton and chromaplex i also dose with reef biofuel i run normal filter pads and purigen packs any thought on what im doing wrong appreciate the help in advance