t’s not difficult once you understand how it works. Every pond is different and is influenced by the amount of sunlight/shade, nutrient it receives from external sources such as dust/pollen, leaves and run off, the number of fish, feeding practises etc so there is always a learning period until you get it right. Often the best action is no action at all and the pond will find its balance. Take your time and observe, its not a swimming pool that you can simply bomb and forget – its alive. Is there good flow through in the pond or are you simply pumping from directly under the waterfall? If so then the rest of the pond is not being filtered and you have stagnant areas where algae readily grows.
The larger the body of water the more resilient or stable it is to change from factors such as temperature and nutrient loads. Aquatic plants not only look good and provide habitats for fish and insects but also buffer the pond by consuming nutrients in the water. The secret lies in providing good biological filtration and by minimising the amount of organic material such as leaves and detritus collecting on the bottom of the pond. – We use purpose build pond skimmers to remove leaf, dust and pollen fall and a good biologic filter which becomes the launching place for the waterfall – its all hidden. Its important to provide habitats for naturally occurring bacteria to convert nutrients to forms that are readily available for aquatic plants to consume.
Often algae is seen as the problem, it’s actually just the indicator of excessive nutrients or an unbalanced system. There are two main types – string algae or blanket weed and the free floating algae which makes it self know when the water goes that pea green colour. Algae is just natures way of mopping up excess nutrients. A good population of aquatic plant swill compete with algae and help to maintain a clear water pond. A pond should have different defined depths built into it from the shallow for marginal plantings to the deeper areas where water lily’s and oxygenator plants thrive. It’s not often in nature you will find a single depth or bowl shaped body of water and there is a reason for that. By placing pebble over a good quality pond liner you create habitats for bacteria and plants which then make the entire pond a large biological filter. A UV steriliser will only partially treat the free floating algae and not the string algae. The steriliser will also kill beneficial bacteria in the pond often making the situation worse. Work with Nature not against her.