Green water feature
I have a circular water feature which is 7 inches deep and about 30 inches wide. Frogs love it and live in it all year round, I have tried growing pond weed in it to try to keep the water clear but it still goes green. I don't want to use anything which will harm the frogs, but would dearly love the water to be clearer. Are there any water plants which would grow happily in such shallow water and would help to oxygenate the water and stop it going green?