Advice on my wildlife pond please

Madelinew · #1 (**permalink**) 14-06-2009, 07:23 PM

I have 2 wildlife ponds in my garden. The lower one is fed by a small stream that runs through my garden and water pumps twice a day from the lower one to the larger upper pond to refresh the water there. I'm inundated with wonderful newts and various other beasties but my tadpoles have had a really hard time and have been finished off yet again by the wretched stringy green algae that has taken over for the third year running. I've used barley straw which has just had the damn stuff grow straight over the top of it. I've tried all sorts and am now reduced to raking it out - fairly ineffectively.

Yes I have waterlilies for coverage and yes I've tried about everything that has been suggested when I've asked about it here. I have a few other plants growing there too.

Would it help if I install a fountain? In which case can someone suggest a cheap option to try please? There is a lot of silt in the bottom full of my beasties. I have a few other plants growing there too. I have also just seen a suggestion that bagging up lavender cuttings and dropping them in the pond might help and that's not one I've heard before. Any good? I have loads of lavender.

In addition I have another problem. The dry weather recently has meant that the stream is running very low. I haven't got a great deal of fresh water coming through the system. As a result, the lower pond is now a mass of flies which is not very pleasant. Stream water is still coming through but before it runs through to the other side where there is an outlet that rejoins the stream, most if not all of the excess water is evaporating from the pond surface. I'm loathe to put tap water in for 2 reasons - I suspect that this will add to my algae problem and also I am on a water meter.

I would like to install a small fountain anyway especially to help with oxygenation if that's possible. The pond in question is a meter deep and has a diameter of approx 3 meters.

So to summarise

What cheap fountain can I use on my top pond?
What can I do about the water supply in the bottom pond?
Would bags of lavender make any difference to the algae?

Cheers!

Wetnwild · #2 (**permalink**) 15-06-2009, 09:03 PM

You're probably best off comparing internet prices for a cheap fountain pump. If you look at the litres per hour it should be quite easy to compare different models. You might have trouble with the filamentous algae clogging the intake, though. Fountain pumps have to have quite fine strainers, by necessity. I don't think the pump will make any difference to the algae problem, but it might help the wildlife if deoxygenation is a problem.

Lavender and barley straw act against green water, rather than filamentous algae.

I don't think there's much you can do about the filamentous algae except pull it out as necessary, as you are already doing. Unfortunately it sounds like the conditions in your pond are just right for it (as they are in many ponds). It does have wildlife benefits, though - it forms the basis of food chains, and gives shelter to invertebrates, etc. I don't usually find it affects tadpoles, myself. Erecting a pergola over the pond to drastically shade it seems to work well against filamentous algae, but this probably isn't something you want to do.

If you don't want to add tapwater, I can't see what you can do about the low water levels in the bottom pond until the stream water levels increase naturally.

Madelinew · #3 (**permalink**) 16-06-2009, 01:16 PM

The reason it affected my tadpoles is that they seem to have got stuck in it in the past. They'd congregate around the edge of the pond to feed on it there and as the heat of the day evaporated a little of the water, they got stuck. That and they proved easy pickings for the local birdlife especially my crows.

I'll just keep on raking. Thanks for the advice

Am I right in thinking that adding tapwater to top up the slight drop in water levels could exacerbate the algae problem?

Wetnwild · #4 (**permalink**) 17-06-2009, 08:43 AM

You'd think the tadploes would have more sense, wouldn't you?

For some reason mine have never done that: I have a couple of very long troughs containing water plants for sale, and hundreds appear in these. As the season advances the toughs get full of blanket weed and you can no longer see any tadpoles, but they seem to emerge as froglets in summer quite happily just the same.

Yes, tap water would probably make the algae worse, it depends on whether the tap water is higher in nutrients than the water that runs through the stream. It's possible your stream water might run off fields or something, and carry a lot of fertiliser, hence the heavy filamentous algae you get.

Madelinew · #5 (**permalink**) 17-06-2009, 11:50 AM

You're probably right about the source of the water. It does start up on farmland somewhere.

My pond now seems utterly devoid of taddies and I haven't seen a single froglet. Next year, I plan on scooping some of the spawn out and helping it along to a certain level before returning any tadpoles to the pond. It's been interesting watching the causes of their decline but a shame I have absolutely nothing left to show for the masses of spawn laid in there earlier this year.