Question
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Followup To
Question -
How do I prevent recurrence of a brownish film/slim that appears mostly on rocks of the waterfall.

Thanks for your reply.

The water color is clear rather than brown.  The brown is like a film or sludge attached to the rocks themselves.  It can be removed mechanically but comes/grows back quickly.  Would you think this film is microbial in origin? Is there a treatment/product I can use to prevent/remove it?

I have hyacinths and water lilys in the pond.

Answer
Check the PH of your water it should be somewhere between 7.3& 7.4 if it is far from this try to correct the PH chemically and find some pond peat it usually comes in a nylon bag if you have a filter put it in the filter or just sink the nylon bag of peat it helps stabilize the PH. The only chemical I know of is the regular pond algacide. It causes the algaie to float to the top and you have to scoop it.

         Keep Ponding
         Leigh