Greetings, I have a very small 50 gallon pond. I found a large number of tadpoles living in some old buckets at the back of our property last year. They were quite crammed so I bought and installed a preformed pond to give them a better home. It was great fun to watch them transform into frogs through the summer. Many have returned and we have a new batch of tadpoles in the pond this year. The pond has no filter but I have several floating plants (water lettuce and water hyacinths). Last year, the pond was new so I fed the tadpoles finely chopped spinach (which they loved). This year there is algae growing on the roots of the floating plants. I offer the tadpoles spinach, but they are not that interested. I have concerns regarding the clarity of the water (not as clear as when the pond was new). I remove some water and add fresh water every other day to be sure the pond does not get too stagnant. Any guidance on maintaining a healthy pond for the tadpoles would be greatly appreciated! We love the sounds of the frogs at night!