Added Tetra Algae Control, milky water

[Joker741]

I was getting some algae in the 90 gallon tank, so I added some algae control 3 days ago and now the water is milky cloudy. I have been doing 20 gallon water changes the last two days and it is not changing the water clarity. The chemical levels are all perfect, I just have milky cloudy water. Any suggestions?

EDIT: I have a 90 Gallon freshwater tank with a Marineland Emporer 400, 2 Marineland 200 watt heaters