We recently shifted our pond. The new pond has plants growing well and already the lillies cover about half the surface but algae started growing from day one (ie green water). The old pond never had algae of any kind.
I've been looking into barley straw for algae prevention in the new pond. The science seems good. The decomposing barley has an enzyme that inhibits algae growth without inhibiting plant growth or harming fish. Some other plants have a similar effect but barley is supposedly the best. The studies were not in NZ.
Then I found that the enyme is available in liquid form. Supposedly safe for fish, but I'm not sure I trust that. Yet.
On the other hand, the old pond that never had algae was under a cabbage tree and had years of cabbage tree leaves in the water. I used to scoop out the excess, but there were always some there. Cabbage trees do that. So I'm wondering if the cabbage tree leaves have a similar enzyme to the barley straw process. I have put a few leaves in the new pond in the hope of getting the cycle started. But with algae already there, it may not work well, even if the theory is right.
My questions here are: does anyone have experience of using barley straw and/or the liquid enzyme in a pond? Does the liquid enzyme work? And is it safe for fish? Or does anyone else have experience with cabbage trees dropping leaves in ponds? Did the pond get algae?
Thanks very much.
kaylin,
Feb 15, 6:08am
Wow. N I have no experience with either only I'd be really interested if cabbage leaves work.
devine-spark,
Feb 15, 6:16am
I used to use a product that was meant to cure algae issues without upsetting fish or plants, however it killed my lilies. Is your new pond getting too much sun? Maybe the cabbage tree kept it shaded?
koru67,
Feb 15, 8:32am
We emptied our pond at the end of last year as our last remaining old fish had gone to fishy heaven and I wanted to refresh the pond before adding new fish. I had the same problem as you with terrible algae even though I had plants and a UV/biological filter running. I bought a pond zyme biological product that is supposed to help clear the sludge and now has barley in it (the old one I bought years ago did not include barley, same brand and product). That dropped the PH eventually but did not help with the algae. So I used the barley straw liquid and after 1 dose it worked, did take about 2 weeks to show fully though. I did not lose any fish or plants from using it. Our pond is 600L.
bluefrog2,
Feb 15, 8:44am
I would have thought it was due to the new pond getting more sunshine than the old pond. I have a couple of water drinkers out for my hens, and the one that is in full sun has started growing algae on the surface even though I change the water every two days. I have to scrub it. The drinker in full shade never has any algae. But while you're sourcing barley straw, why not throw in some cabbage tree leaves and see if that works!
raewyn2,
Feb 17, 6:48am
Thanks everyone. Koru67, I'm intrigued at your mention of pH so I checked the pond. It's pretty much exactly 7 which is a little bit higher than it started out, and probably better for the fish. While I was doing that I also tested all the other paramters and although it's only 4 weeks into its cycle, the ammonia, nitrite and nitrate were all 0. And there are babies too. So everything is good except the colour. I think I'll go ahead and buy the liquid barley enzyme. If I can get rid of this new flush of algae the cabbage tree leaves might then be able to cope long term. Taking 2 weeks to clear sounds good. I wouldn't want it to be too sudden and stress the fish with rotting algae. I'll find this thread again in the future and update how it went since a couple of you have indicated interest. Cheers.
poolgirl6,
Feb 18, 9:00am
I buy the barley straw, place it in a old panty hose, leave it until it needs replacing, and it works for me. No green algae despite too much sun on the pond which is about 500 litres. A cheap alternative, to the liquid. Give it a try.
raewyn2,
Feb 21, 4:21am
Out of interest, where do you buy the barley straw? I couldn't fined any except whole bales from Canterbury. I bought the liquid extract and will see how it goes. I used half the recommended dose for starters. It just needs to tip the balance back away from the excess algae and I think the plants will take over OK. And I have left the bunch of cabbage leaves in place.
Several people have mentioned sun. Yes, the new pond gets more sun than the old, which is a good thing. Algae needs light to grow, but needs less light than the plants. So if you have very low light nothing grows. Or if you have very bright light and vigorous plants then they should outgrow the algae. Exceptions are when other conditions such as excess nutrient also feed the algae. The trick is to get the right balance.
oh_hunnihunni,
Feb 21, 4:49am
Oak leaves work too, I think it's the tannins.
rojill,
Feb 23, 7:25am
1 / To reduce algae growth the water temp needs to be as low as possible therefore minimum pond water depth should be greater than 700mm 2 / Add 5 gms Copper Sulphate per 1000 litres of water. 3 / Good luck
samanya,
Feb 23, 8:13am
You are aware that any pond depth exceeding 400mm may be required to be fenced . by law? I agree that the cooler the water the less problem with algae growth, that's why planting & providing shade works & the bonus is that plants also take up any algae promoting nutrients in the water.
poolgirl6,
Feb 24, 8:18am
Raewyn2 I purchase mine from a dedicated fish/ pond/pet store.a smallish packet costs very little and lasts well. Do try it. It needs replacing when it gets smelly every few weeks.
devine-spark,
May 28, 7:23am
I have a pond that is 12m by 2.5m by 400mm and am looking for a good way of covering it so that it still looks good but is safe. I have been looking at some sort of grid mesh like reinforcing mesh, possibly in marine grade stainless steel (yes expensive), but still have not nailed down a good option. Thought about creating an outside frame with legs to the bottom, and mesh on top and fixing it to the sides. Any thoughts people? It is hard in ChCh to get someone handy to do the work. Various steel work companies out there but all too busy. It has got to look good as it is a formal pond in a nice garden. but I now have a grandchild starting to crawl and safely is first. Not going to drain it as it has fish and I want to keep it. but not take risks.
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