Summer's all about keeping everything healthy and ticking along nicely in the garden - and the same goes for ponds. As with all gardening, 15 minutes upkeep every week or so will keep everything in check. Leave it to its own devices and, after a few weeks, the job will probably turn into a bigger one!
Ponds are often trickier than other areas of the garden - neglect them in summer and they can quickly turn into an eyesore! Unless you want a jungle swamp, add the pond to your regular tasks for peace of mind.
If your pond is becoming green and smelly and doesn't clear up, you may need to check the ratio of pond plants to water - they should be evenly matched - or whether your pond is too much in the open sunshine. Consider more shading plants as marginals to counter this.
Weed your pond as you would your borders. Apart from visible pond weed and algae, there'll be weeds to get rid of in between pond-side plants too. Plus, your oxygenators, which do a great job under the surface to increase oxygen levels, can get a little out of hand, so chop them back before they take over.