The best way to utilize barley straw is to place it in a mesh or net
bag, and allow it to float on your ponds surface. So not submerge it.
Once its wet and starts to degrade, it forms a peroxide which is not
harmfull to fish etc but devastating to algae. I used two bales of
barley straw one year in my pond and it virtually killed all of the
algae. Pond is approx 1 surface acre and I had a heap of straw pats
floating in mesh bags and you could definately see a difference in the
water around the bags slowly spreading outward till they all
overlapped. Of course water temp and sun has a lot to do on how fast
it works but it does work. Can't say if it will work if its submerged
or not, and I would not think it would have any detrimental effect on
a pond but I would remove it from a container or liner type pond after
it does its job, as any rotting material will eventually buildup stuff
thats not good for a small pond. A natural bottom (dirt) pond it
should not matter all that much if its of sufficient size.
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