An Update: the mess I started talking about in the original post actually is like this: water is not brown, the brown coor is actually a visual efect. I took a water sample in a white bucket: the water has a green color.

So I guess I do have an algae bloom you were talking about. I have been monitoring all I can (and all my budget lets me). Here is some new/uodated data:

I have not started the aereation in the hole quarry, just is a section of it with a good amount of aereation. At the beginning the bubbles (diffuser installed at 33 feets deep)/and water comeing from the bottom had a really strong sulphur smell. There was a really well defined separations of waters in the middle of the water column.

Now after some weeks of aereation, I have this algae bloom. But also I have noticed a huge increase in zooplancton. The sulphur smell has desapeared, at all. There is no sulphur smell comeing out, and also in the bottom (I dove in the quarry and in the past you could sense this smeel even being underwater close the bottom).

1 week ago I added a product: benefical bacteria. It is aimed to consume the nutrients the algae needs, so I guess I should see improvements of this algae bloom soon?

My objetive is to have clear water, right now it look like Im going in the oposite direction since before starting the aereation, there was a zone of clear water (from surface to 20 feets deep, deeper than that there was a really dark brown area of sulphur smell zone).

Im in the right path? what else would you recomend me
Thanks inadvance for your sugestions