Biological Solution to Algae

At the risk of being labeled a quack, I want to remind you all that with the coming of the summer it is time to replenish your stock quantity of barley straw.

Not all algae infestations are the same, but in most cases barley straw can cure the problem algae overgrow. We know the biological process works, but often don’t seem to work the way it should. If you do not get the success you should, here is a guide for using barley straw...


Barley straw works by way of a biological process. The specific species of microorganisms that digest the lignin component of the barley straw produce toxins that inhibit algal growth. And the nature of biological processes is that it is not a simple on-off switch. You need the right species of organism in the minimum number, and you need time for all to grow to a balanced system.


So the first rule is obvious: You must have enough straw to produce enough toxins to kill algal cells at a rate faster than they multiply. If the algae multiply at a greater rate than you are kill them, you fight a losing battle.


Remedy? First lower the algal count. Remove or dilute the algae physically or treat chemically, then the barley straw will control it. You can also simply increase the dose of straw to ultimately out-perform the algae, but this may be costly.


Important: if you clean the pond out to get rid of the green soup DO NOT CLEAN AND SCRUB the pond sides and bottom. Just lightly hose it down. Get the bits of uneaten food and organic matter out, but leave the sides. That “carpet” is a host of living organisms and an extension of your biological filter. The biofilm there is more important than the physical algae.


The second rule is not to overstock/overfeed. While overstocking beyond the capacity of the pond ecosystem is potentially hazardous, overfeeding adds unnecessarily nutrients for the algae and adds to the nitrate concentration of your pond. If that is your pond I’m talking about, flush more regularly, get rid of the buildup of nitrate and organics. Also think of incorporating some plants in the returned water. Such a vegetable filter can become an asset.


The third rule: Get the right species of barley straw with the right species of algae munching fungi. We know by experience that the Overberg barley straw works in most cases. It the straw you use does not work, try a different type of barley straw. If despite all your efforts the algae still seem to control you, consider the possibility that the specific strain of algae is resistant to the barley straw toxin. Then you have no option but to completely kill it chemically, and try again.


Barley straw does not make your UV sterilizer redundant. A good working UV unit with matching flow rate and pond size is vital to keep the buildup of free-floating bacteria in the pond. Usually they do battles among themselves and control themselves, but is some cases they get out of hand and a typical bacterial pond syndrome develops. Then you have ulcers in your future.


Servaas de Kock


Read more about barley straw...

Read more about bacterial pond syndrome...

Lignin = Building material of the cell structure of plants that gives it structure and rigidity.