Backyard Aquaponics
A place to discuss aquaponics

Hi,
our system (35.000L) has a very high phosphorus load.
We think its a problem of the last fall where many leaves falls into the pond and we saw them this spring and removed very much of them.

Do you have an idea how to remove a high load without adding chemicals ?


Thanks Dom

Can you just plant masses of fruiting plants?

Water changes could do it too. Do you have a system thread? I'd love to see it.

How have you diagnosed the P levels, and what ppm do you have? I would not have thought that leaves in general would be a big source of Phosphorus, animal wastes would have much higher P levels.

If P is way too high you may see a large algal bloom, is that happening?

For a remedy, as Colum suggests, change your water or put in heaps of tomatoes.

Hi and thanks for your reply.
You can found our system on our homepage www.lets-grow.de
The pond was covered some weeks but we don't see the fish and the hole garden looks not very nice.
Now after three days the water turns green and we can't see the fish.
We checked with a phosphorus water test.
I can't tell you the amount because 1ml pond water to 4ml tapwater has more than 3mg/L.
So it would be > 20mg/l.

In our region lives many wild cats.
So it can be possible that they use it as toilet...

Can you repeat the test, using distilled water instead of tap water, and diluting further? My system often has >20mg/l, but that doesn't last as the plants use it up quickly.

Same result.
Season in germany is at the last two month

I don't think that plants will suck up.
And we only have plants without fruits.
Salad, bet rot, radies, kohlrabi and beans ...

ummm I wish I had excess P.. but high fruiting crops like tomatoes.. cucumber.. pumpkins are your best choice... btw what is your ammonia levels..?

Yeah - ship some over to me my system generally has 0-1ppm P when I measure it with oodles of Nitrate.

Had a look at the website, though no pics and no Sprechen Sie Deutsch.

Are you growing tilapia??? Would be one hell of a heating bill!

I think your options are
:change the water
:wait till summer to grow nutrient hogs like tomatoes - cover tank in mean time
:turn the system into a greenwater system and stock algal eaters

Whatever you do, you'll need to ensure plenty of aeration to prevent oxygen starvation if you've got an algal bloom, and be ready for Ammonia/Nitrite spikes when the algae all die.

Google has a handy translation thing.

https://translate.google.com/translate? ... t=&act=url

I can't seem to find an overview images of the whole system, just individual pictures of beds. Looks nice though.

Thanks Column . found this pic of a tank - only 1000L though:

http://www.lets-grow.de/index.php/proje ... -kiesbeete

Alot of salad going down Need a few more toms!!!

Good morning my friends,
thanks for your response.
No the 1000l system was the first of the three outdoor systems.
Here is the site where i built the pond
http://www.lets-grow.de/index.php/proje ... chbau-2013

You're right, i have to make a overview of the beds, the pipes, the filter (4m³) and the pond (35m³).
Yes we're breeding tilapia but not for the big system.
There we're using common carp which has a actually size between 20 and 40cm.

Yes you're right with the idea of cover the pond, but looks not very nice and can't see the fish

I'll try to make a phosphate precipitation with iron.
When iron is in water it starts to rust and creates ironhydroxyd.
Phosphorus react with them and you got ironphosphorus which isn't soluble in water.

Are your leafy greens going to seed/bolting quickly?

And that pond would have been fun to dig out.

Yes of course no problems with them.
We harvest 180 luttuce this year, so we can't see any more lettuce this season

I'm thinking about the lava in my filter...
Do you think that the lava can raise phosphat ?

I'm curious about your test for the phosphorus. It's supposed to encourage fruiting in plants, so very high levels should be making the lettuce or any green leafy veg bolt/go to seed before they normally would. That's why commercial systems with tomatoes & lettuce are usually separated.

Have there been any signs of high phosphorus? Other nutrients being locked out?

Difficult to say.
We're adding iron chelate and epsom salt for the lack of nutrience /signs of...