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Anaerobic alkaline substrate - iron, natural products?

D

Desmond007

New Member
Joined
10 Apr 2023
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8
Location
Denmark
Hi all

I'm doing a fish tank with a dirted substrate capped with fine sand, so the substrate will be
anaerobic. I'm putting cat litter, calcium, Vermicompost, peat moss, soil in the substrate
so pH will be neutral to alkaline.

Which forms of iron should i use, for plants to have easy access to it?
Are there any natural products i can use for iron in
a neutral to alkaline substrate?
Laterite or/and moler clay for example?

thanks!
 
Hi all,
Desmond007 said:
@dw1305 Any suggestions?
Click to expand...
I think if the substrate <"is a reducing environment"> then ferrous iron ions (Fe++) will be plant available. However I think you are likely to have problems with root growth, and I would want <"some emergent plants"> with <"roots adapted to deep substrates">. You would need these plants to create the zones of <"fluctuating REDOX where iron uptake can occur">.

I'll be honest it is a bit of a strange combination, and I wouldn't advice it. Are you trying for a "traditional" Walstad tank without water changes or water movement?

cheers Darrel
 
dw1305 said:
Hi all,

I think if the substrate <"is a reducing environment"> then ferrous iron ions (Fe++) will be plant available. However I think you are likely to have problems with root growth, and I would want <"some emergent plants"> with <"roots adapted to deep substrates">. You would need these plants to create the zones of <"fluctuating REDOX where iron uptake can occur">.

I'll be honest it is a bit of a strange combination, and I wouldn't advice it. Are you trying for a "traditional" Walstad tank without water changes or water movement?

cheers Darrel
Click to expand...
Thanks!
I'm trying a Father Fish tank. Lots of people from around the globe
talking about their healthiest tanks after using his system.
He's on Youtube.
I dont think root growth is a problem, since the plants are good at finding the nutrients they need i think, even in a 2" inch sand cap and with a 1" dirted soil layer underneath
 
Ok, no worries.

A bit above my paygrade, but i found this comment some time ago:

Ferrous iron is more readily available to plants BUT it will also readily bind and turn into a solid reactiving with other ions especially if it's wet (in a solution) like being in a fish tank. If the soil pH level is higher than 6.5 then iron availability is lower for the plant to uptake through its roots/ rhizomes because the iron will bind to other ions particularly calcium carbonate..."

So i guess i'm looking for chelated iron from a natural source?
 
H all,
dw1305 said:
"Father Fish Tank", I'll be honest a new one on me. I'll have a look and get back to you.
Click to expand...
I've had a look, and I'm not convinced is probably the answer. Have a look at <"Soil Substrate or Dirted Tank - A How to Guide">

Personally I'm not keen on organic and nutrient rich substrates, and I also don't think that any tank necessarily has a finite life span, mine have run for over ten years with very limited intervention. It is back to <"orchids and tomatoes"> and I'm, very much, an <"orchid"> grower.

My suggestion is that, yes you can have limited intervention, but feed both the plants and the fish, have some water movement and change some water. <"Walstad revises">.
Desmond007 said:
If the soil pH level is higher than 6.5 then iron availability is lower for the plant to uptake through its roots/ rhizomes because the iron will bind to other ions particularly calcium carbonate .....So i guess i'm looking for chelated iron from a natural source?
Click to expand...
You can use <"citric acid as a natural chelator">, it isn't very effective, which was why FeEDTA etc. were developed for <"commercial hydroponics">.

Plants are very effective at manipulating the rhizosphere to make nutrients available (or unavailable where toxicity may be an issue), so I rather have <"good root growth"> with the microbial community "managed" with radial oxygen loss etc.

cheers Darrel
 
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Desmond007 said:
Laterite
Click to expand...
I have no faith in laterite as a biologically available source of iron. It can be cut into bricks for building. Better to use a chelated iron source. I am also not a fan of anaerobic substrates in aquariums. I have such substrates in 50L bucket ponds but they have emergent plants, small water lilies in season (out of doors) and a clump of papyrus grass in the one in the conservatory.
Basically I agree with @dw1305 above.
 
Ok thanks for your input.
For me it just makes sense. Capping the soil and additive substrate with sand so it doesnt leach nutrients into the water column.
Additives for the first 12 months and after then a biodiverse microbiome is developed in the substrate.
Microorganisms that feed the plants nessasary nutrients when they need them.
You feed your tank with wild leaves full of micro and macroorganisms, leaves break down, sifts into the substrate, feed the microorganisms, turns to humus and locks up carbon.
I need to try it out lol.

What kind of systems/substrates do you guys run?
 
Hi all,
Desmond007 said:
What kind of systems/substrates do you guys run?
Click to expand...
Sand as a substrate, with a <"very minimal amount of leaf mold and clay mixed in">. Once the substrate is in place I try and leave it undisturbed. I have Malaysian Trumpet Snails (Melanoides tuberculata) in my tanks, so there will be some substrate turn-over.
Desmond007 said:
with sand so it doesnt leach nutrients into the water column.
Click to expand...
I use as floating plant as an indication of <"when to add nutrients"> and <"have a lot of ferns"> etc. so I want the water column to contain <"enough nutrients to support plant growth">.

I'm using <"Solufeed 2 : 1 : 4 mix"> as my fertiliser.

cheers Darrel
 
dw1305 said:
Hi all,

Sand as a substrate, with a <"very minimal amount of leaf mold and clay mixed in">. Once the substrate is in place I try and leave it undisturbed. I have Malaysian Trumpet Snails (Melanoides tuberculata) in my tanks, so there will be some substrate turn-over.

I use as floating plant as an indication of <"when to add nutrients"> and <"have a lot of ferns"> etc. so I want the water column to contain <"enough nutrients to support plant growth">.

I'm using <"Solufeed 2 : 1 : 4 mix"> as my fertiliser.

cheers Darrel
Click to expand...
Youre sand substrate isnt anaerobic?
I guess it depends on the depth.
Since im trying this Father Fish dirted sand system, and its gonna be anaerobic, and i have no idea of the final Ph of the substrate (i just know that its anaerobic) , would it be an idea to add Vitax Sequestered Iron Plant Tonic,
since its got so many different kinds of iron chelations.?
 
Hi all,
Desmond007 said:
Youre sand substrate isnt anaerobic?
Click to expand...
It maybe in patches. I'd look on a <"gradient of REDOX values"> <"in the substrate"> as a good thing. Have a look at <"Aquarium Biofiltration - SWISSTROPICALS">.
Desmond007 said:
Vitax Sequestered Iron Plant Tonic
Click to expand...
That should be all right. I'm guessing that the <"Chempak Sequestered Iron"> mentioned elsewhere is this product re-labelled.
Desmond007 said:
and long term iron (like Moler?) that takes a long time for plants to access
Click to expand...
I'm guessing that, in most situations, that iron (Fe) is insoluble for all of eternity. I think the Danish Moler clay deposit is <"50,000,000 years old">, so long term could be very long term indeed.

cheers Darrel
 
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