Backyard Aquaponics
A place to discuss aquaponics

I have developed a serious string algae problem. Currently don't have any filtering system minus whatever my grow media (coco coir) and plant roots filter out.

My pond is 25' long x 4' wide x 5' deep...around 3600 gallons. Currently stocked with yellow perch.

I'm looking at this filter: https://www.amazon.com/XtremepowerUS-Aq ... d_sbs_86_8

Will this suck out all the beneficial plant nutrients? Obviously I don't want to do that, but I think I need something to help clear up my pond. It's totally green and can't see any fish unless they are a few inches from the top. The coco coir also stained the water so I have those tannins going on.

For those of you with larger systems, what are you using?

Thanks!

Keep the sun off it and the algae wont grow in the first place. Have you tied netting it out?

I have been netting it every couple days but it's not taking care of the strings on the sides of the pond, or the smaller particulates floating around. Here's a video showing how bad it is: https://drive.google.com/open?id=1B9oLF ... lWU6cH1IdG

Nice looking setup . I have some thoughts but I'm not sure what you've tried...

You could cover the tank or part of the tank to gradually kill off the algae. It's better if the die off is gradual so that you don't cause oxygen level issues that could cause a fish kill (seems pretty unlikely in this case but it could be a problem). I would reduce the fish feeding since that's contributing to the problem. I notice the water hyacinths don't look very healthy, are they dead? This makes me think the water temp is pretty low and if this is the case your bacteria in the media beds may not be doing much biofiltration. What's the water temp and what type of fish are you growing?

If your plants are actively growing and the temp is high enough for the bacteria to act, killing the algae by depriving it of light should allow the plants in the beds and the bacteria to use up the phosphates. Without available phosphate the algae will have a tougher time getting a start. You should be able to uncover the tank after this without much of a re-bloom unless you're system is out of balance. Might help to plant more plants as well.

Barley straw is another option that might be worth a try. I've never used it but it has worked for some.

Usually the algae goes away once the system kicks in and never comes back unless to much phosphate gets back into the system water (usually by overfeeding and/or insufficient bio-filtration).

Edit: Couldn't quite understand the narrative on the video although it's probably because of my hearing problems not your audio. I caught that the hyacinth was dead but not the cause.

That's the most impressive algae growth I've seen in an AP system! You don't appear to have much aeration going for the size of the FT. I suspect your O2 concentration is not very high, you need to clean out that algae more frequently.


This was my aeration in my large system, about 2/3 your water volume, but I have doubled the air since then, and it creates significant waves across the surface.

viewtopic.php?f=18&t=24153&start=105#p507035

The stale water,rotting matter & nutrients plus light = gunky algae.
Block out the light.Also what's the Nitrate reading?


"died over winter & is decomposing"

Thanks

Thanks all for the responses! The water temp is starting to heat up as we move into the spring, but currently it's around 50 degrees. The system is inside a greenhouse and is not indoors, so there is a natural temp fluctuation through the seasons.

Yes, the water hyacinths died over the winter and began to decompose.

The type of fish are yellow perch.

I have tried barley straw without success.

I am definitely going to add some shade over the pond for awhile to cut down on the algae growth.

There is also mention above about increasing my aeration. For a 3600 gallon system what do you think would be a sufficient size? Any product recommendations? Currently using a system I purchased from Amazon for around $50, but it's probably not getting the job done.

Was also considering putting in a couple christmas trees and some mosquito fish (so they can have places to hide), but wasn't sure if they would be able to sustain population from the perch eating them. I like the idea of some natural algae control from those and pond snails, but don't want to just buy hundreds of $$ of quickly disappearing fish food haha.

Also, I'm not sure how to go about getting a ntrate reading. What's the method for handling that?

This system was designed by a company called "Garden Pool" in Arizona, who told me that the Yellow Perch would be able to survive on eating my pond plants (I had azolla, duckweed, water lettuce, and water hyacinth). All were growing very quickly last summer. Is this realistic?

My main issue right now is I would LOVE to be able to see the fish. I have no idea how many they are, and can't catch any blindly with a net because the water is so dark. I am tempted to buy a biofilter and run it for a week to clean it up, but don't want to screw up any beneficial bacteria in the water.

Google "wood ash for pond algae". Seems wood ash might help. You decide.