This is a brand new pond, isn't it?
How big is it (rough volume and depth)? and how much direct sunlight does it get?
Don't despair, heavy algae growth is perfectly normal for a new pond. But, in case there's something else going on you need to look at the nutrient balance:
Inputs:
Are there any sources of nutrients leaching into the pond? Common sources are tapwater (contains a little nitrogen, minimal phosphates), decomposing organic matter (doesn't sound like it from your description, but includes falling leaves and decomposing plant matter) and ground run-off (avoid using fertilisers where the run-off can enter the pond.
The other potential source is compost. Only ever use aquatic compost for planting baskets in the water. It's formulated to contain almost no nutrients, so (in theory) it won't fuel algae growth.
It's essential to minimise nutrient inputs. Scooping out leaves, removing dead plant material, avoiding accidental fertiliser run-off.
Outputs:
Aerobic bacteria in filtration systems can oxidise ammonia and nitrites to nitraes (animal wastes) and anerobic filtration can reduce nitrates to nitrogen. As you're not keeping fish this isn't going to be neccessary, the pond should be able to cope with frogs and other natural wildlife without a filter. It will cope with a very light fish stocking level without a filter if it's large enough.
Uptake by plants and algae. Your soup of algae is doing you a favour at the moment, it's taking up the nutrients in the water and converting them to algae drymass. "Gloopy water" sounds like it could be hair algae. If it is, you're in luck as it's ease to remove by twisting a bamboo cane or stick the the water until it wraps into a mass you can remove (and compost). If you keep removing the algae from the pond to the compost heap you will be removing the nutrients that the algae extracted from the water. Consequently, providing there is no additional source topping up the nutrients, the nutrient levels will fall and the algael growth slow down.
It's important to keep harvesting algae and oxygenators little and often as the real benefit in reducing the nutrient levels in the pond only happens when you remove algae or plant matter from the pond. If you just leave it, then come winter it will die, decompose, release the nutrients and you're back where you started next year. Removing the algae will also allow the other plants to do better.
If the algae is slimey, not at all hair like and forms sheets or blobs.. then you might have cyanobacteria (sometimes called blue-green algae, but it's not an algae and it's not a bacteria). This is also quite natural, but usually indicates very heavy nutrient levels and/or poor light levels. You should be able to net this out when it clumps, and then look to address the nutrient levels and consider if there is enough sunlight on the water.
There is an idea that shading the pond will rid it of algae. Whilst it's true that algae will die when starved of light, they then decompose and release their nutrients back into the water. It over-looks one very important thing; algae is good for your pond. Not having algae when the nutrients are present in the pond to fuel it's growth is worse than having the algae visible. The excess nutrients are worse than the algae. The algae is natures way of dealing with the nutrient problem you didn't know you had.
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September 23, 2007, 22:05