How to fix string alge in stream when there is NONE in the main pond?

[MaureenCaballero]

Please answer me as if I don't know anything (because I don't know much about water, ph, algae fixes, etc). I have approx 3000 gallon aquascape pond with a waterfall that dumps into a 12' stream. The pond is about 2.5 years old. While I have had algae issues in the main pond (sometimes pea soup), currently it is crystal clear in the main pond, which does have an auto-doser of Maintain beneficial bacteria.) Is there something I should do at this time of year to minimize the string algae in the stream, so that it's not just worse come spring? I'm barely feeding my koi (only about a few minutes of cold season food, 4 times/week). I'm pulling out about1/3 of a 5 gallon bucket of string algae every week. Thanks for any advice!

[fly4koi]

Manually rake them out is the best, chemical kills them and they just decompose in the water which doesn't help with the nutrients staying in the pond.

[Matt24]

... I'm pulling out about 1/3 of a 5 gallon bucket of string algae every week. ...

Sounds like good maintenance. Other than aesthetics, the algae probably is not hurting anything, UNLESS it gets to making the stream back up and causing overflow or if it is breaking loose and clogging up your pump.

I wonder if back-flushing the filter to remove some of the nutrients would help reduce algae growth, along with making sure leaves are dipped out.

If you don't have pond plants and the string algae gets to annoying you too much, it can be knocked way back by 0.15% - 0.20% salt for a couple of weeks, and then reducing the salt with water changes.

[MaureenCaballero]

Manually rake them out is the best, chemical kills them and they just decompose in the water which doesn't help with the nutrients staying in the pond.

Thanks! I guess I was just wondering if there is something else I should be doing, but it sounds like manually removing the string algae is best. Thanks.

[MaureenCaballero]

Ok, that is reassuring that I'm not doing something wrong that is causing the string algae to propogate. Not sure what you mean by "back-flushing" the filter -- I DID pull out the filter mat and hose it down since it had quite a bit of muck on it. Also, since it is looking better now (maybe because I hosed off the filter mat or just because it is colder now), I'm not going to do anything to alleviate it now. BUT, like you said, if it gets to be too annoying next spring and I want to "knock it back", how exactly do I "do" 0.15% - 0.20% salt for a couple of weeks? (remember I've done pretty much nothing with my pond except for adding beneficial bacteria on a regular basis and manually removing the string algae -- I'm a newbie! Thanks.

[Matt24]

... Not sure what you mean by "back-flushing" the filter ...

It depends on how your filter is designed. Most filters (as far as I know) have some way to periodically drain or flush out the gunk that the filter has been filtering out. I've only ever used home-made filters on my ponds, and I always put a hole near the bottom of the filter with a valve. So every few months, I stop the pump, pull out the filter media, including he pad (mat), after swooshing it around some to rinse it a little in the filter's water, and open the valve to flush out that brown gunk.

... I DID pull out the filter mat and hose it down since it had quite a bit of muck on it. ...

I used to do that, but found that swooshing the filter mat around some to rinse it a little in the filter's water does a reasonably adequate job, without killing bacteria with the chlorinated water from the hose.

... BUT, like you said, if it gets to be too annoying next spring and I want to "knock it back", how exactly do I "do" 0.15% - 0.20% salt for a couple of weeks? ...

The koi calculators page has a form where you give it your pond's volume and the % that you want to change the salt level, and it tells you how much non-iodized salt (with no additives) you need for that.
https://www.koiphen.com/forums/koicalcs.php?do=calcsalt
I've used Morton Rock salt and also solar salt. I think some like that for better purity. Also it is best to change the level slowly, not more than 0.10% per day.

After a couple of weeks, you can start doing water changes to gradually lower the salt level. I once ran into koi health problems (bacterial infections) when keeping a 0.30% salt level for months on end, abut the problems when away when I lowered the salt level. Also, some pond plants are harmed by salt.

[BWG]

Crystal clear main pond is what most strive for and many do not succeed. Why mess up a good thing? Just manually harvest the excess. Filters convert waste to less harmful plant nutrients (fertilizer). Given fertilizer and light some type of algae is going to grow. Fortunate for you it's not in the main pond.