k2so4 reacts with soil?

[nkambae]

My soil based 10 gallon tank with no CO2 and approximately 1.2 LED watts per gallon was showing signs of K deficiency (holes in leaves of C. wendti). I dosed small amounts of K2SO4 and my leaves became unholy (sorry, couldn't resist). In relating this on another forum I received the advice that K2SO4 could react with or be changed by the soil to form sulfides and or hydrogen sulfide gas. It was suggested that KCl would make a better supplement.

I have been doing some googling and reading on the various forums and can neither confirm nor refute the assertion. My questions are thus:

1. Is it possible for K2SO4 to react with the soil to give me bad gas? (should I dose some Bean-o as well?)
2. Is Muriate of Potash (K2O) an acceptable alternative to supply K instead of K2SO4?
3. Do the same dosing levels of K2SO4 apply to KCl? This question is in regards to EI dosing in my other tanks.

The Muriate of Potash in question is the Hi-Yield brand distributed by Voluntary Purchasing Groups, Inc. out of Texas. The guaranteed analysis is 60% soluble potash (K2O). I dunno what the other 40% is... maybe Cl? Sulfate? Nevermind, the MSDS supplied by Hi-Yield lists the chemical formula as KCl.

Any advice, thoughts, and especially, scientific observations from any and all would be greatly appreciated. Thanks.

stu

 

[Tom Barr]

H2S only forms under very strong reduction, which can only occur when there is a lot of organic matter in the sediment. I mean a lot.

There's plenty of SO4 already in the water, never mind the sediment.

Holes in the leaves are not a sign of K+ alone, it could be CO2(much more likely), and you can easily add K+ to the water, and out an end to that easy enough.

Regards,
Tom Barr

 

[nkambae]

thanks

So I should only worry about K2SO4 reduction if the cattle feedlot upstream from my tank has a breach in its settling pond? Oh I'm sorry, sometimes I just can't resist being a smart aleck. I will be less concerned about adding small amounts of K2SO4 and continue it as it did seem to clear up the issue of holy leaves. At least that's the way it seemed because I didn't change any other parameters. I do do my best to change only one parameter at a time so I can observe cause and effect to the best of my ability. Could be wrong though. Believe it or not, I've actually been wrong once or twice before.

Any ideas about my other questions? KCl vs. K2SO4 as an alternative source of K in an EI tank? Or any other tank, for that matter. And any inputs about equivalent dosing levels, i.e. 1/8 tsp K2SO4 = ? tsp KCl, would be appreciated. The reason for my curiosity about KCl is that it is cheap, available locally, and I don't have to pay shipping. Thanks again.

stu

 

[Tom Barr]

So I should only worry about K2SO4 reduction if the cattle feedlot upstream from my tank has a breach in its settling pond?

Yep, high loading rates= strong reduction.
Rare in aquariums though.

Oh I'm sorry, sometimes I just can't resist being a smart aleck. I will be less concerned about adding small amounts of K2SO4 and continue it as it did seem to clear up the issue of holy leaves. At least that's the way it seemed because I didn't change any other parameters. I do do my best to change only one parameter at a time so I can observe cause and effect to the best of my ability. Could be wrong though. Believe it or not, I've actually been wrong once or twice before.

Any ideas about my other questions? KCl vs. K2SO4 as an alternative source of K in an EI tank? Or any other tank, for that matter. And any inputs about equivalent dosing levels, i.e. 1/8 tsp K2SO4 = ? tsp KCl, would be appreciated. The reason for my curiosity about KCl is that it is cheap, available locally, and I don't have to pay shipping. Thanks again.

stu

Well, you should be able to rule, out the K+ issue quickly, however, I do nt think it's a K+ issue, and your holes shall persist.

That will suggest CO2.
If the tank was limited from K+, adding t will increase the CO2 demand, so you went from K+ limited, to CO2 limited.

KCL should be okay also, but only addresses SO4.
Tap likely has plenty SO4.

So you do not gain from that one.
I think it's a CO2 issue.

Regards,
Tom Barr

 

[nkambae]

If the tank was limited from K+, adding t will increase the CO2 demand, so you went from K+ limited, to CO2 limited.

Forgot about that. So if I reduce demand for CO2 then demand for K (and everything else) drops as well. I will raise my lights a bit and shorten my photo period by 2 hours. Then I shall observe for a couple of weeks and reassess at that time.

KCL should be okay also, but only addresses SO4.
Tap likely has plenty SO4.

I'm not so worried about SO4 anymore. I talked to that farmer upstream and he assured me that the earthen dike surrounding the settling pond is solid and won't give way. I'm understanding that I can use KCl instead of K2SO4 since it is easily accessible and cheaper for me than K2SO4.

Thanks again.

stu

 

[illumnae]

Reviving an old thread with a follow-on question. From my understanding of the above, this question seems to relate to dosing K2SO4 in a tank using soil.

I've recently decided to use mineralized soil as my base substrate. Part of the "recipe" calls for KCl to be sprinkled underneath the soil. Some "gurus" have advised that K2SO4 is not suitable for this as the SO4 will form Hydrogen Sulphide and kill off my flora and fauna in the long run. While this won't happen with water dosing, will it happen with the K2SO4 deep underneath the soil?

I understand Tom has stated that K uptake of plants is not done via the roots, hence the K under the soil is useless. However, this question would relate also to MgSO4 and CaSO4, which I would like to put under the soil as well as part of the recipe to mineralized topsoil. The K2SO4 is a by-product as I intend to use Seachem Equilibrium, which contains K2SO4 on top of the other 2.

 

[JDowns]

I think for that to become an issue you would need a good deal of organic matter and low O2 levels for the ates to become ides and then cause problems. But this happens in tanks where folks do not add these elements, so I'm not sure where folks are coming from on this. If you've mineralized correctly your organic matter should be no where near the %'s needed for that to happen.

 

[JDowns]

I guess another question along these lines would be. Does Ca and Mg bind well to the soil, or is it to like K, just leached into the water column?

 

[Tom Barr]

Reviving an old thread with a follow-on question. From my understanding of the above, this question seems to relate to dosing K2SO4 in a tank using soil.

I've recently decided to use mineralized soil as my base substrate. Part of the "recipe" calls for KCl to be sprinkled underneath the soil. Some "gurus" have advised that K2SO4 is not suitable for this as the SO4 will form Hydrogen Sulphide and kill off my flora and fauna in the long run. While this won't happen with water dosing, will it happen with the K2SO4 deep underneath the soil?

I understand Tom has stated that K uptake of plants is not done via the roots, hence the K under the soil is useless. However, this question would relate also to MgSO4 and CaSO4, which I would like to put under the soil as well as part of the recipe to mineralized topsoil. The K2SO4 is a by-product as I intend to use Seachem Equilibrium, which contains K2SO4 on top of the other 2.

They are wrong.
For SO4 reduction to occur, the soil must not be mineralized...........that is why they mineralize in the first place. Mineralizing the soil pre oxidized the organic matter, without a lot of reduced organic matter, the redox levels will attain the ranges required for Sulfur reduction.

A "Guru" of any sort would possess at least an iota of mastery of wetland sediment cycling and should/would know this

Even a person with common sense would also realize, that you have already oxidized and mineralized the sediment, that is the point in doing step
I'd not listen to those that tell you this honestly.
They do not know what they are talking about.
No way to be nice about that one.

Plant roots also add lots of O2 to sediments where planting is dense.
Take a look at a planted tank after a few months from underneath.
What do you see?

A network of roots everywhere.

You can add MgSO4, CaSO4, they both have SO4 as well, so does most everyone's tap water, there's plenty of SO4 for reduction in otherwords, adding a bit more via K2SO4 will not influence reduction in sediments. In very soft peaty sediments, under high reduction, high organic loading, those systems can become SO4 limiting for sulfur reducing bacteria.
But high organic loading is detrimental to fish and O2....so unless you overfeed and add way too much food etc daily, this is not going to occur.

I'd chose dolomite for a source of Ca and Mg.
It will last a long time and supply the Ca/Mg needs.
Most tap has a fair amount and evaporation losses and additions often add enough. Depends on how high the GH is, but heck, adding GH booster once every 2-4 weeks ain't hard either.

Plants take up Ca, Mg, and K via the leaves mostly i n nature, but they can and do take up all nutrients via the leaves and can do so for the roots as well, most all plants can.

They use fertigation for this reason, this is what all aquatic plant nurseries do BTW, and 95% of all ornamental horticulturist for terrestrial plants. They use rock wool or Sand and Bark. No soil.

Regards,
Tom Barr

 

[illumnae]

Thanks for all the responses, especially your long and detailed one Tom!

I'd pick dolomite too except that it really isn't available here in SG. I've searched garden centres, LFS and can't find any. That's why I wanted to put Seachem Equilibrium under the substrate together with some coral chips to make sure the substrate doesn't turn acidic and release heavy metals. That's part of the MTS "recipe"

 

[Tom Barr]

There is no recipe specifically for MS............never was, just this latest batch of folks think there is some new secret they happened upon.

Soil is the main part there, and with most of the organic matter gone, you can do this by a shallow pan with water for 3-4 weeks, or by cooking it for 1 hour at 400-500F, or by boiling it for 10 minutes, all these things oxidize organic matter.

If you look at the earth worm castings suggestions on the sticky, they suggest boiling it. Soaking it prior works. ADA uses low OM% but it still releases a lot of N, so they suggest water changes until the sediment mineralizes in the aquarium.

In otherwords, all soil based methods do the same thing one way or the other.

At the lab, we go out to where we find aquatic plant(river Delta, we go at low tide, it's FW but tidal influenced, bring buckets and dig maybe 20 buckets worth and drag them back to the lab.

We get a wheel barrow, a large screen with 1/8" holes and a garden hose sprayer.

The heavier clay soil washes to the bottom of the wheel barrow, and the fines over flow. After a few buckets, we allow the water to settle, then decant off the water. Then allow to dry some till it's a nice clay paste.

The washing oxidizes most of the material, plus is already wetland sediment to begin with. Screen removes all the larger pieces of twigs and other organic matter.

We also have tested the sediment for %OM, so we know it's perfect for what we use it for: growing aquatic plants in pots.

That's my recipe, works better than any of those others too
How do I know?

I've tested it with Eurasian milfoil with 5 replicates in a flow through tank at 200 micromols.

Since the tank is flow through drip type, there's nothing in the water column and the leaching from different sediments has no effect since it's washed away as soon as it leaches out.

You cannot test different sediments independently unless you scrub the water column rapidly and/or have a flow through water system, so continuous water changing. I doubt most know how much %OM they have in their MS..........I don't unless I test for it. Never met a single person that has tested it in the hobby.
So that's a big unknown for all of them.

I'm clueless/wrong but they are the experts

Folks have been using soil, clays (Cat litter) etc for at least 60-70 years from the pictures I've seen and have.

Adding amendments generally do not harm anything, help?
Hard to say unless you do a replacement test with pots.
I sort of doubt most of those items help.

Seems adding a little bit of ferts to the water column once in awhile is a wiser move.

Certainly grows plant better doing that rather than trying to cram every last nutrient in the sediment. I do not think that is a good horticultural approach.

I'd be happy to send you some of the MS clay we use, but you are in SG so that's a lot for ship $$.

Go to a stream in Malaysia that's a nice forested area and dig up some nice stream mud with some sand, some clay mix. Let is settle in a shallow pan for a few days, 7-14 etc, then rinse slightly, and let settle and dry out till it's clay like.

Then add that.

This is not some hard thing to do or figure out.
That's the point.

Regards,
Tom Barr











Regards,
Tom Barr

 

[illumnae]

Thanks Tom I managed to find some topsoil finally here, so I've been working on that. I doubt my wife will let me use the oven/her pots to boil/bake the soil, so I've been doing it the old-fashioned way of washing/drying.

So I actually don't have to add anything at all under the MTS once I'm done? All I do is mix the clay in and I'm all set?

 

[illumnae]

Sorry next question. Would it be harmful in any way if I were to mix in some bamboo charcoal into the MTS? I figured with some mulm to kickstart the bacteria culture, the bamboo charcoal could act as colonizing spots for them. Further, the bamboo charcoal chips could break up the soil abit and lengthen the time before it starts compacting into a solid mess. Finally, as bamboo charcoal has a high CEC, it could help in transporting nutrients to the roots when the soil eventually hardens up?

All the above are unsubstantiated postulations, I'm really clueless about this and just wondering