Products which can help to manage pond algae fall into three categories - biological, enzymatic and physical. Biological products manipulate the aquatic environment through introduction of bacteria which feed on excess nitrates and phosphates in the water, reducing their availability to the algae.
Enzymatic products disrupt the molecular structure of weed, causing the plant to completely break apart.
Finally, there are two main types of physical products - dyes which reduce the amount of sunlight penetrating below the surface of the water; and products which capture the algae within a substrate preventing it from absorbing nutrients.
Dr Graceson recommends understanding why the algae is growing excessively in the first place, to help inform control methods and product selection. With no authorised traditional chemical control treatments, often physical intervention will be required once algae have become established.
She added: “Enzymatic products are likely to assist with the control of existing problematic algae, but most treatment options are most effective when applied preventatively, or at the very start of visible signs of excessive algal growth.
“If sufficient amounts of algae are removed through physical methods, such as through raking, then a bacteria-based product may then help with ongoing control.
“If you are concerned about removing aquatic creatures during physical removal of algae, leave the algae at the side of the pond for a short while so they can return to the water.”
For further algae control advice, contact enquiries@agrovista.co.uk