I've had my pond for about 7 years now and love it! The minnows reproduce like no one's business without any feeding or taking care of, the iris and water lillies look beautiful, etc etc.

But.... I can't get rid of string algae!

The pond is a 125 gallon top pond waterfalling into a 200 gallon lower pond with a UV filter designed for up 900 gallons (top of the line filter) getting fed with a 520 gph pump. I've never had serious problems with string algae until this year. I pull pounds and pounds of it out every weekend to no avail. I've tried barley which seems to slow down the growth not at all after I remove the algae (I know it only works on algae-free ponds, does not kill string algae). And I'm currently trying algaecide I bought at homedepot. I started adding the recommended amount, and now I've been adding twice a week instead of the recommended once a week with no success.

Anyone have any other ideas on how to battle it? I know limiting sun exposure, but with a pond so heavily planted I wouldn't have expected it to be an issue.

Thanks a lot!

Someone told me once that Japanese trapdoor live bearing snails will eat the algae.

I tried the snails route as well, but unfortunately it grows far faster than snails can possible eat. Thanks though!

sounds like you need to get to the root of the problem..might be time for a snorkling expedition. Have you tested the water..something is very high..i will probably same phosphates..is this pond out in the open or is there trees around it.., and is the algae in the upper pond or lower pond..if the pond is out in the open you dont get any brighter light than the sun..also how much are you feeding, take away algae food source..it dies, but i am curious if the algae is in the upper , lower or both.i get that anser i might be able to help you a little better..

good luck

Rick

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POWER to the FISHIES

Thanks for the reply!

Interestingly enough, the algae is only in the top pond now. I have been adding algaecide to the bottom pond and it has seemed to fix the problem. I figured it would get pumped up to the upper pond but alas not. I will start adding algaecide to that pond as well and see what happens. I will also add some barley bales to both ponds once I kill all the algae. Finally, I planted some more water lillies up there to block some of the sun and am going to purchase a solar floating fountain from Harbor Freight to add some more shade and circulation.

With response to your questions; I do not feed the fish at all. Someone, the 3 rosy red minnows I started with in the bottom pond have multiplied to hundreds with no care whatsoever and have even ended up in the upper pond as well! They must have survived getting sucked through my UV and biological Filtoclear 800….

When I last tested the water everything was totally fine, with no levels out of the normal range. Embarrassingly enough, my pond which receives little care had better water quality than my two fish tanks I am constantly working on.

Any other suggestions or thoughts would be very appreciated! Thanks!

And the pond is halfway in the open with holly bushes on one side. Thanks!

sorry for the late response..been having internet issues..ie..not internet..your not getting the algae in the lower pond because thats where the pump is and you have more circulation there than it the top pond..algae doesnt like water water flow..i would almost bet that the stream going from the top to the bottom also has no algae..pleanty of water flow there. i would try putting a powerhead in the upper pond and see if that helps.

Rick

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POWER to the FISHIES

In my opinion, winning the battle of algae is done with a good biological filtration. I've got a great diagram and lots of information to share. We had problems with hair algae in some ponds and suspended algae in others. Once we started using this downflow bio-filter, our problems with algae disappeared.

Your's Koily, Lorraine