My oxygenating plants are becoming covered in alge ...

Hi Caveman, well, algae in the water is a sign of too much nutrients in the water. Also some of the plants put out very fine green/brown roots that can look like algae. Washing the roots will clean them but it won't get rid of the problem if it really is algae. Could you post pics of your pond and is it in Sun, partial shade or shade??

 

Well, strange as it may seem I wouldn't wash them as yet. Your oxygenating plants are part of the natural system to will use the nutrients to grow and do their job of oxygenating. The nutrients won't just disappear as I'm sure you know, you need a constant process of extraction and I do that in my pond by planting in the margins with plants that will use the nutrients. You're going to get sediment and decaying debris in the pond and if you've got fish they will add to it when they excrete. It's just a matter of getting the balance right with plants and making sure there are enough to take out more nutrients than is going in.... and a bit of patience Being in the Sun will give the plants the light they need but it will also encourage algae to grow, but algae won't grow if your plants are depriving them of nutrients by using it themselves.

 

Nice one Caveman..
I have found it takes a pond around 12 months min to set it's own eco system up & the plants establish themselves.. The full sun will cause the algae to grow as it is all so new & also fairly shallow.. So you will have to expect that for a while... Although hateful stuff duckweed also serves a very valid service in shading the water... Perhaps get a water lily, not my thing, but that will help to shade the bottom of the pond a bit..Oxygenating plants are necessary but will also cause algae to grow as well.. Why not see about getting a small net of Barley straw & popping it in as that is very good, but I think most of all you need some patience to let it settle down & the plants to start working... Despite what the tv progs say there is no instant pond.... It has to go through it's own establishment now..