We put a small garden pond in at my folks house, and it keeps filling up with algae. They have tried different products of algicide to keep it down, but it still takes over. Does anyone care for these ponds that might be able to help us out? Should we run acidity/PH tests on the water? They have plants in it, and even a few fish, but they end up emptying and scrubbing it out about once a month or so. Any advice is appreciated.