Algae trouble.

[Insomniak]

This is my first year with a wildlife pond in my garden, until now I just had a bunch of tubs and tanks with plants and a generous coating of duckweed on all of them, so I never had an algae problem.
Now I'm noticing that the stones on the "beach" part of the pond are covered in green slimy blobs and the little roots of the duckweed are matted together with similar green slime.
I've just got some AlgiStraw and have one pad of it floating.

By the way, the pond 6ft x 5ft, is up and running for 4 months now, plenty of plants growing in it and duckweed covering approx a third of the surface, many snails, water slaters, daphnia, worms and more living happily in it, no fish and as yet, no frogs.

Should I try to *wash* the stones and clear some of the algae or just wait and let the Algistraw do its job?
I think it only prevents new algae growth, it won't do anything for the already formed algae.

I could do with some advice, please!

[tom00_uk]

sounds like blanket weed,

did you fill it with tap water and provide lots of nutrients?

get some more plants growing to use up the excess nutrients,

personally i hate duck weed and speed a hour or two a week skimming off the stuff from my pond, and in doing so removing the nutrients it has locked up onto the veg patch

if the stones are just green then thats not a bad thing, many organisums can now graze on them.

[Deb London]

Green slimy blobs and such are the foundation for a healthy food chain, which makes for a productive wildlife pond. Don't add or allow leaching of fertilizers or tap water, and the pond will balance itself naturally. Rejoice in your green slimy blobs and overlook their ugliness.

[Insomniak]

Originally Posted by tom00_uk

sounds like blanket weed,

did you fill it with tap water and provide lots of nutrients?

get some more plants growing to use up the excess nutrients,

personally i hate duck weed and speed a hour or two a week skimming off the stuff from my pond, and in doing so removing the nutrients it has locked up onto the veg patch

if the stones are just green then thats not a bad thing, many organisums can now graze on them.

No tap water, I filled the pond from the tubs and tanks I already had plants growing in, added some rainwater and waited for the rain to fill the rest.
I put in all the sediment and silt that was bound up in the roots of the plants, so I thought I got it off to a reasonably good start.
It's only in the last 3 weeks that I've noticed any algae at all.

Blanket weed under the duckweed? Hmm... that could be it, it's definitely stringy slime I see when I scoop up some of the duckweed.
So, in effect, there are two separate things going on: The blobs on the stones which are ok and the blanket weed which is much less desirable.

Should I aim for having more than half the surface of the pond covered in some form of growth to lessen the sunlight getting to the water?

[Insomniak]

Originally Posted by Deb London

Green slimy blobs and such are the foundation for a healthy food chain, which makes for a productive wildlife pond. Don't add or allow leaching of fertilizers or tap water, and the pond will balance itself naturally. Rejoice in your green slimy blobs and overlook their ugliness.

Having spent much time on my knees looking into the pond, I do know that the hundreds of worms are continuously moving around near the blobs, and the water slaters too, so I guess they're in their element in that case!
No tap water and nothing draining into the pond, so I'll wait it out, maybe scoop out some of the slime under the duckweed and see if it all balances out, I'm sure the Algistraw will help a bit. Thanks!

[Malcolm Banks]

People seem to report different levels of succes with various anti blanketweed treatments. I have found straw treatment singularly useless for BW, but others swear by it and it is certainly good for single-celled algal bloom problems. To some extent the pond may balance itself out but I have tried every device to reduce the nutirents in my pond and it still keeps coming back. Fortunately there are a couple of (biological, not chemical) treatments that I have found to work reasonably well, but BW is a bit like a herpesvirus, once you've got it it is quite difficult to eradicate it completely. As I have discovered though it can be "managed" to enable a pond free of overt BW contamination.
You will probably get as many suggestions as replies, but there's my penn'th
(NB the skaters are strictly carnivorous)
M

[Insomniak]

Originally Posted by Malcolm Banks

People seem to report different levels of succes with various anti blanketweed treatments. I have found straw treatment singularly useless for BW, but others swear by it and it is certainly good for single-celled algal bloom problems. To some extent the pond may balance itself out but I have tried every device to reduce the nutirents in my pond and it still keeps coming back. Fortunately there are a couple of (biological, not chemical) treatments that I have found to work reasonably well, but BW is a bit like a herpesvirus, once you've got it it is quite difficult to eradicate it completely. As I have discovered though it can be "managed" to enable a pond free of overt BW contamination.
You will probably get as many suggestions as replies, but there's my penn'th
(NB the skaters are strictly carnivorous)
M

I think I'll attempt to scoop out as much blanket weed as I can, even at the expense of the duckweed, I know it'll never die out. I have some plants grown from seed, a few Irises and a couple of Spiral Juncus that are almost ready to go into the pond, so hopefully that in itself will help solve the problem.
As the Water Slaters feast on decaying matter as well as dead animals, can we expect them to eat algae too? How convenient would that be!

[Malcolm Banks]

Yes I found it extremely relaxing to spend a while twizzling blanketweed out with a pea stick, and satisfying to get a big lump with the dark green bits at the bottom. At the risk of offence I should repeat the obligatory and necessary mantra of leaving the weed at the side of the pond. I did find that damselfly nymphs in particular appear to like hanging out in BW.
This manual removal activity is fine but leave it for a few days and, especially in the summer, it will be back in abundance. Hopefully your plant additions may have a beneficial effect but certainly made no perceptible impact on the BW in my pond.

Re pond skater's diet - Convenient it would be if they consumed plant matter but sadly I am pretty sure they eat animal material only, which they inject with proteases and other catabolic enzymes, as well as paralysing agents. (not much evolutionary advantage developing a paralysing protein for plant material)

What would be nice to know would be if blanketweed has any natural "predators", I've masses of snails but they don't appear to eat BW and certainly don't impact on BW concentration.
Anyway, good luck with your efforts!
M

[tom00_uk]

Grass Carp (Ctenopharyngodon idella) is cited as being good for the removal of blanket weed, but you have to ensure it can not escape into the wild. not native and not sutible for a nature focused pond.

i have the other problem my ponds to clear, its over a meter at the depest and you can still see the bottom, at the start of the season its feed to try and encourage the phytoplankton but its soon clear again.

[Malcolm Banks]

Yes Tom00, I think I would prefer to keep the blanketweed rather than introduce fish, especially since I now have it under control. However, I do have friends with ornamental fish ponds that have to heave the stuff out by the armful (largely because of the high nutrient levels in fed-fish ponds) so I will pass on this tip about grass carp - you don't happen to know the source of this gem do you?
M