Soil substrate pond

[Meyer Jordan]

A big benefit of using soil as a substrate in a pond - the soil will adsorb phosphate.
(the Holy Grail https://www.extension.org/mediawiki/files/1/18/Aquaculture_Pond_Bottom_Soil_Quality_Management.pdf page 11)

Important to take note of the fact that the higher the clay content of the bottom substrate, the higher the binding action on Phosphorus.

 

[MitchM]

If you, Meyer, or anyone else for that matter have information about soil substrate, please feel free to post it. I'll be posting updates on my ponds' progress and information as I come across it, but any additional information is welcome.

 

[MitchM]

I started planting the 600g today, I'm slowly taking plants from the the 320g to the 600g because there are still fish in the 320.
It still needs a LOT more plants.
There is a yellow brown tint from humic substances that come from the soil, but that will disappear in time.
Hopefully I'll be able to transfer the fish next weekend. We'll see how the water tests go.
I'm also trying an old 6 foot LED fixture I have for lighting the tank. I still need to get a good idea what's really needed.
The 320g pond setup in the greenhouse won't have any lighting on it, except maybe during the winter, we'll see how that goes.

 

[MitchM]

After I set up the test 40g tank, I added enough ammonia to bring the level to 3ppm and a little over 1 week later, ammonia is reading near zero, so that tells me that there were plenty of nitrifying bacteria already present in the soil.
The plants would certainly be having an effect on reducing ammonium, but my API test kit does not distinguish between ammonium and ammonia. (ammonium is more prevelant at lower PH, ammonia more prevelant at higher PH) Plants like ammonium, not so much ammonia.
There is still too much of a PH difference between the 320g and the 600g to consider moving the fish (6.9PH vs 7.8PH, respectively) I'm using increased aeration and water circulation to raise the PH in one tank and eliminating aeration and reducing circulation to lower PH in the other tank.

Nitrates in both soil tanks are about 40 - 50ppm, I've been testing every few days and have never detected nitrites.
Tropical tank nitrates are 10ppm.

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[MitchM]

Having watched the amount of gravel a koi can suck up in one go looking for scraps of food or invertibrates , ...
Dave

That's not necessarily a bad thing Dave.
If the koi disturbed the gravel enough, that could allow detritus to get to the soil layer quicker, and to the plant roots quicker.
Of course there's the problem of uprooting the plants, but there may be a way of protecting them maybe with some mesh screening.
I would like to try a couple of koi and transfer them to the outside pond as they grow bigger but I think even a single small koi would overload the natural filtration capacity of a 320g tank.

 

[Dave 54]

That is indeed true Mitch koi are noted for their waste production my friend
But looking good so far I'm following this with some interest

Dave

 

[MitchM]

The tricky part Dave is trying to determine what is an acceptable load for a biofilm/soil/plant filter.
So far the only way I can find is to keep track of ammonia levels.

 

[MitchM]

I got the fish transferred out of the greenhouse pond this week, that all went well.
Today I emptied out the tank, put in the rocks first so as not to compact the substrate.
Then I put in about 1 1/2" of garden soil, capped it off with 1 1/2" of 7 mm gravel.

 

[MitchM]

I need to figure out a way that I can incorporate a bog or marginal plant container into this setup. I thought maybe a plastic tray that sat up on the edge of the tank and drained back into the pond.
The tray could be filled with peat moss and gravel.

Anyways the pond is filling now with straight well water.

 

[Meyer Jordan]

I need to figure out a way that I can incorporate a bog or marginal plant container into this setup. I thought maybe a plastic tray that sat up on the edge of the tank and drained back into the pond.
The tray could be filled with peat moss and gravel.

View attachment 83423


Anyways the pond is filling now with straight well water.

View attachment 83424

Do not use peat moss. It is highly acidic and will destabilize the pH. Peat moss has a pH of 4.0 - 4.5.

 

[MitchM]

What would you suggest instead, coconut coir?

 

[Meyer Jordan]

What would you suggest instead, coconut coir?

Why not use just gravel, no organic additive.

 

[MitchM]

Water PH is probably going to be between 7 and 8. I was hoping to have some carnivorous plants (if I can find them here) and I thought they preferred a lower PH environment.
My topoff water is quite hard if I use well water, or I can use RO.
Haven't decided yet.

 

[Meyer Jordan]

Water PH is probably going to be between 7 and 8. I was hoping to have some carnivorous plants (if I can find them here) and I thought they preferred a lower PH environment.
My topoff water is quite hard if I use well water, or I can use RO.
Haven't decided yet.

Carnivorous plants are true bog plants and do prefer a very acidic environment, but a true bog does not have any moving water except when it overflows. It is fed strictly by rainfall. Your proposed set-up would expose the plants to 2 different pH levels and would gradually lower the pH of the pond water.

 

[MitchM]

In that case I'll probably look at a separate set up for carnivorus plants.
I'll continue on with typical marginals.
Thanks for that.