I have considerable ...

I have considerable experience with this problem,  perhaps I can help.

You said  Fish Pond Systems - plural.  So, I assume this is a series of fish ponds used to grow fish for commercial purposes.  Correct?  If that is the case, it changes the normal approach to controlling algae because we are looking at a possible nutrient overload situation from two sources:  the food that is not consumed, and the food that is and winds up as fish feces in the pond.  Fish do not produce the same feces as mammals or other animals because their kidneys are not developed in the same way.  So we look at the ammonia, amines, nitrites, and nitrate levels.  

Thus, the normal algaecides should not be used alone. and the algaecides used for ponds is much different than those used in cooling towers: we sell both types. In addition, in the US, the pond algaecides must be EPA approved for that purpose: if you ignore it is big fine and jail time.  

Now then, the last gentleman talked about Barley Straw which has sone some promise because of the specific bacteria that grow on Barley straw.  It is much cheaper to purchase the bactera, along with a few others that give a digestion of the nutrients without harming the fish or the handlers. We have come up with a blend of 8 bacteria strains that have done a good job for shrimp farming overseas, and catfish farming hear in the US.  We have successfully used the same bacteria blend for the removal and digestion of diesel fuel spills.  

But, you should also have an initial spot treatment with an algaecide for a properly identified algae  because the governmental agencies both in the US and Europe have restricted the use to specific spicies application.  There are several chelated coppers that work well, but the species of algae will have to be identified.  

Think this through, because one doesn't want to kill the fish, or have a poison carry over and kill a consumer of the fish.

Forget about grass carp, they don't eat algae: they do eat vascular plants - that is why the are called grass and not called algae carp. 

Forget about using chlorine - that will kill the fish by burning their gills. 

Precipitation with aluminum will not work, because you want to kill the algae off by any method that works. They just don't fall out very well, and that doesn't kill them anyway. I just think it will take two methods to obtain control because this has been my experience.  A specific approved algaecide for the quick kill and the kill on the edges of the pond, and a bacteria for the removal of the nutrients.  This bacteria reproduces and doubles in population about every 15 minutes, so it is first to the dinner table: ahead of the algae. 

Another problem to point out in this quickly sent message is pH.  You have to monitor it. The bacteria grow best in a pH from 6.5 minimum and preferably 7 to a pH of 8.2 the point where P alkalinity stops and the chemistry of many things change.  Above 8.2 to about 10 the algae grow best.  The two groups are competative, so in situations like this I like to circulate a little acid (not phosphoric acid because you get PO4 as an algae nutrient) to lower the pH from the ammonia added by the fish. 

I hope this helps

Waymon E. Hofheins

President, Blue Valley Laboratories, Inc.

Kansas City, MO