Pond conductivity

 

Conductivity in my pond since the beginning

Conductivity in my pond since the beginning

A techy one – it’s a while since I reported on my garden pond’s conductivity. But its still looking good: usually less than 100, and currently right down below 50.

Conductivity is a good rough guide to the condition of ponds. It measures how much ‘stuff’ there is dissolved in the water. And ponds which are polluted usually have more ‘stuff’ dissolved in them than those that are clean.

The good thing about conductivity is that with a portable meter you can get a result that’s almost as good as a laboratory can produce. This isn’t true for most other pollution measurements where to get a useful result you usually need to get an expensive laboratory test.

A conductivity below about 250 and the pond will usually turn out to be in pretty good shape. Over 600, and usually there will be problems. Between these two values and you need to look carefully. I was looking at a village pond with conductivity of 1100 the other day – and that definitely has problems. Not so far from here, we were looking at a posssible site for Million Ponds clean water ponds. The water had a conductivity of 700 and so not much chance it would be unpolluted.

As water chemistry specialists will know conductivity is only a rough guide to pollutant levels  – but you can make surprisingly good assessments of the overall impact of pollution is you interpret it carefully.

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4 Responses to “Pond conductivity”

  1. mkono luzuba Says:

    What are the recomended conductivities for fish ponds?

  2. Elliot Says:

    Conductivity is a very American way of measuring a form of water quaity. In the UK a more common way used is water hardness and also the amount of dissolved ions present in water. When talking about the conductivity measured in microsiemens, I would recommend that in a water body keeping fish, you should be more worried about keeping it above a minimum of 200m-s so that there are enough ions present for the fish to effectively osmoregulate unlike what is posted in the article. And again as is stated reading over 900 m-s is cause for concern. The best way to remove this is an instant water change and then to locate the source of the problem.

    For more help and information please visit http://www.essex-aquatics.co.uk or email info@essex-aquatics.co.uk for more help

  3. Jeremy Biggs Says:

    Hi Elliott – I don’t really agree. Conductivity is used by freshwater biologists all over the world including this country – it’s certainly not particularly ‘American’. The Environment Agency, for example, would make probably 100’s of thousands of routine conductivity measurements. And there must be thousands of waterbodies out there in the countryside that have plenty of fish, and conductivities below 200. I expect that many western and northern salmon rivers, for example, would have conductivities well below this. I guess in captivity it is harder to keep some cyprinid type fish (and perhaps many others too) in low conductivity water, and as you say some fish do have quite tricky osmoregulatory requirements.

    Jeremy

  4. Elliot Says:

    Hi Jeremy,

    Many thanks for your input. Your quite right with respect to salmonid species, however for the point of the article and ponds, normally keeping cyprinid species, I have angled my reponse towards this. Hence the lower limit I recommended of 200ms for a garden pond and wished only to help people with this.
    I hope this was ok and fully appreciate your post and it was a pleasure reading and conversing with you on such a topic.

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