dukydaf

Today i tested the water in the pond and it came NO3=0 gH=11 kH=6 but pH=9 . Oups how do my danios live in there but the echinodorus is not really growing. The pond is house to many danios , 2 goldfish, 3Corydoras paleatus and many plants. It is currently plagued with green water due to improper filtration.

I do not know where did this ph came from?

I used potted soil with sand to pot the echinodorus. The sand is almost neutral and the soil is said to be neutral.

Does anybody have any idea what caused the problem and better how can it be solved ?