Black Oozey Algae Covers Everthing
We have had our pond for three seasons, and the first two came without issue (minor string algae but nothing we couldn't handle). This year, about half way through the summer, we have had a black, slippery ooze cover every surface below the water line including rocks, plants, plant baskets, and lights. It's a black ooze (maybe dark, dark green) that is extremely slippery and almost impossible to get off. A normal jet sprinkler did nothing, and even a stiff brush didn't do a whole lot. There's no way you could scrape it all off anyway as it gets into every crevice and pit of every rock. Anything covered, hidden or the underside of rocks did not get covered. The filters were absolutely disgusting with this ooze. Note that water quality throughout this period was excellent - it was never a water quality issue. Some have said to not worry about it (it's nature) but we miss all the beautiful coloured rocks and river rock we installed (at considerable cost).
Pictures show the difference between the colours above water line and black below. Picture 1792 shows the best contrast - bright colour is what the whole rock used to look like (a piece broke off).
Anyone else have this issue? Suggestions? Thanks.
Notice the small gravel looks quite clean. That could be because your fish are enjoying the banquet and can get the algae off these small rocks better. Anytime you have more algae than you like one of the best things to do is clean your pond to get rid of at least some of the nutrients that feed algae. I'd also guess (hope) that as time goes on and the cycle of the pond aging continues you'll probably see less of the dark algae that concerns you. I recommend bacterial water treatments probably weekly. and maybe cut back on fish feeding to reduce nutrient levels. You have the right high surface area gravel base so it does look like you're doing everything right. Check out Aquascapes water treatment line and hopefully you're already using either our liquid or dry beneficial bacteria. On page 56 of this years catalog we offer an algaecide that would help reduce algae specifically. Finally consider our Automatic Dosing system for liquid water treatments. It constantly drips the treatment into the pond to stay on top of nutrient levels and maintain the best possible water quality with less need to remember when to add the treatments.
Thanks for the comments. It appears that you feel this is definitely an algae problem. I wasn't sure since the stuff was so different than previously experienced. The small rocks got stirred around as I walked on them so the colours are simply stained rocks that turned over. We empty our pond every year as we are in a cold climate so the water is refreshed every spring. I guess I might try a pressure washer the next time I empty it next spring to see if that has the power to remove the goop. I was really wondering why this might have occurred so quickly after two clean seasons so that we can avoid it in the future. Any thoughts on that?
I should also mention that we installed an IonGen this season to try to combat the string algae. Would that have an impact? In other words, is the black ooze a dead algae? And the fish were not interested in this stuff at all, as opposed to the green stringy algae they feasted on the first two seasons. Thanks again for any suggestions.
It surely sounds like you're exactly right on the dead algae issue. The combination of the IonGen and then the fish not nibbling on the "goop" completely supports that thought. And a pressure washer is what our crews use to optimize the removal of algae while the pond is drained. Be sure to lower the IonGen setting to just 1 or 2 once the algae is under control like you've experienced and can even leave the IonGen off some of the time. And ponds as they mature can hold more nutrients and with more fish and larger fish some years algae can grow more. The ecosystem is better established after a couple of years but varying fish feeding amounts, and even rain and sunshine variations can affect how the pond looks. One of the great virtues of these ecosystem ponds is their longevity and overall improvements with age, so hopefully these growing pains will diminish as your enjoyment increases!
Hey, here's a post from another forum that has some suggestsions. Hope that helps.
Originally Posted by lschnell