Mud-munching bacteria and barley straw

Goodness, gracious great bales of straw

Sally mentions in the comments mud-munching bacteria and barley straw as a cure for excess algal growth.

Readers of the blog will know I’m sceptical about barley straw. This is mainly because it doesn’t cure the cause of the problem – which is over-enrichment by nutrients – just (maybe) treats symptoms.

So it is supposed to kill the algae – which maybe it does, maybe it doesn’t (will come back to this).

But it won’t turn a polluted pond into an unpolluted one because it doesn’t reduce nutrient levels (or directly affect other pollutants such as heavy metals, pesticides or ammonia).

Evidence for the effectivenss of mud-munching bacteria is also thin on the ground.

So given the choice between clean water, and applying bacteria to polluted ponds – I would always go for the clean water.

Actually, both treatments are really ripe for some careful before and after experiments on their effect on wildlife – something which has never been done.

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2 Responses to “Mud-munching bacteria and barley straw”

  1. Sally Says:

    Do you suggest doing a complete water change? I am a bit confused because no one ever intends to have polluted water.

  2. Jeremy Biggs Says:

    Hi Sally – I did do that to my new pond (I have two in the garden). When I first made the new pond it ended up wth a conductivity around 350. Given that I thought I’d added only rainwater to it (conductivity in this area usually around 85), and given that my old pond had a conductivity steadily around the 100 mark – I began to wonder.

    I think what had happened was that during the summer when I made it (last year that is) I had accidentally run a load of tap water into the pond when emptying a big paddling pool onto the grass nearby.

    So I bit the bullet and changed the water.

    But…..and this is the but, I was pretty confident that there wouldn’t be any other sources of polllutants around the pond – particularly no bare soil to wash in, and of course the pond had no sediments to speak of at that point (and actually I removed what little there was anyway). Also I can see that you’re keeping fish – which will make the water quality management a bit more more difficult. There’s nothing wrong with fish, of course (I say that because lots of people over here say fish and wildlife don’t mix) but it is more difficult to maintain water quality, in a way that will keep algal growth under control in relatively small ponds, when you have fish.

    So if you were to do a complete water change you’d need to remove sediments too, and be confident that there weren’t other significant sources of nutrients that could run into the pond too – I think in the garden the main risk will be from soil getting into the pond one way or another. But given that you’re keeping fish, and maybe feeding them, it might not be worth the trouble because you’ll soon be re-supplying nutrients just in the normal course of looking after your fish.

    So because we’re all still learning about these clean water ponds – and even though everything says – yes, clean water is key – I’m reluctant to say – ‘just go ahead, it’s absolutely the right thing to do’ because so far we don’t have very much practical evidence of how well water changes work.

    It would be interesting to know a bit more about the set up of your pond – water source, surroundings and so on.

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