A picture of the pond in its current state might help us too.
The description of the water is real important. Putting some in a clear jar and taking a picture with a white sheet of paper behind it would help.
The color can be:
Bright, almost lime green.
Dark green, like a pine tree.
Grayish green.
Brownish green.
How old is the pond?
I assume you don't do water changes (dump out some and put new in)? Doing a water change can help with several kinds of cloudy water and cause more cloudiness for other types. One reason why the pictures are needed.
This is kind of hard question...There's green where if you look really close you see little bits in the water. Up close they may look more light brown/tan. They'd be the size of finely ground pepper and kind of like a snow storm in there.
Sounded like the barley has already been removed? If not it can be. It's just something pond stores like to sell people.
The AlgaeFix on the other hand can kill string algae and other macro algae. How does the algae on the rocks look now? Is it starting to turn kind of sick looking? Less green and more light gray/brown almost translucent? When you touch it is it slimy or feel like horse hair? If the AlgaeFix did start to kill it that could be the source of the cloudiness, bits of dying macro algae. Dying string algae can also help produce what people call green water algae, a single cell algae suspended in the water. String algae can kill the single cell algae so with it hurting the single cell type can get the upper hand.
Sorry for so many questions. Without knowing the cause you kind of have to do everything...fabric filters, DOC, Skippy, UV, etc. Pretty much endless. That can be expensive and frustrating.
You you able to test KH? It's more telling than the pH. 8 pH is not high, imo, it's low.