Reply to Ruth: the sour milk smelling pond

All's not well with Ruth's new pond

All's not well with Ruth's new pond

Ruth has asked whether I could diagnose the source of a sour milk smell in her new pond. She wrote a little while ago:

“Help please!
My new pond smells of sour milk!
It was made for me about 2 months ago.
It’s filled with rain water. It is 2′ deep at the centre and about 2×1.5m surface – it has a logpile next to it. It has lots of wiggly things – some kind of larvae I guess – water now looks quite black. I added some snails and weed from a local pond 2 wks ago.”

So……what’s the answer?

First – I don’t know why its smelling of sour milk, but I would guess that somewhere along the line water quality is a problem.

The rain water is a good start but there’s no reason I can think of why that should go black or smell unless something else had been added to make that happen. A black colour is often a sign of overloading with organic matter.

I wonder whether the emergent plants have been planted in a compost that might be adding either organic matter or nutrients to the pond. It’s also possible that the plants you added (nothing wrong with that) could have died and now be rotting down.

My advice would be to start again: its very difficult to get pollutants out of the water once they’re in – and on the small scale of a pond its perfectly feasible to take the water out, take out anything thats been added to the pond that might be adding pollutants and start again with water that you know for sure is clean.

This is what I did with my second pond when I found it had a conductivity of 300 – nearly 3x what it should have been. I just knew this was a bad start so I chucked the water and refilled it with rainwater.

It may seem like a lot of trouble but clean water, free from added pollutants is so fundamental that it’s worth the effort.

The larvae are probably mosquitos, which are usually amongst the first colonists of new ponds. As other animals colonise they’ll be eaten – mosquitos are usually a very small part of the life in a garden pond, if they occur at all (we have none).


2 Responses to “Reply to Ruth: the sour milk smelling pond”

  1. Gardenpond Magazine » Reply to Ruth: the sour milk smelling pond Says:

    […] more: Reply to Ruth: the sour milk smelling pond Share this on del.icio.usDigg this!Post this on DiigoShare this on RedditBuzz up!Stumble upon […]

  2. Ruth Says:

    thanks, I’ll try changing the water. I have a whole water butt full, plus it’s rainng plenty!

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