Cyanobacteria and green hair algae

All the problems started when I set up alkalinity dosage pump. I have cyano all over the tank and green hair algae on back wall.
Here are my parameters:
Magnesium - 1600ppm
KH (Alkalinity) - 7dkH
Calcium - 440ppm
Salinity - 1.024
Phosphate - 0 ppm
Nitrate - 0 ppm
Nitrite - 0 ppm
pH - 8.43
Ammonia - 0 ppm
Temp - 78.2 F
I also start using biopellets two weeks ago. Biopellets are made by two little fishes.
Okay. I have used Chemiclean to fix the cyano problem. Almost immediately skimmer start to overflow after I add it to my tank . No matter what I did , how I adjust it , it overflow . So I have to keep the bottom drain open. After 24hrs my water start to get cloudy. After 48 hours I replaced about 25% of the water. And it looks like the water is getting more cloudy. What is the problem? I have my biopellets reactor running all the time.