# MTS queries regarding substitutes for dolomite/muriate of potash



## illumnae (Aug 16, 2007)

I've asked the following questions several times on the plantedtank forum, but people there have not been answering. I guess they don't really know the answer  Hence, I'm posting here with the hope that the folks here can help me out. The reason I am looking at replacements for dolomite and muriate of potash is that I'm located in Singapore, and dolomite is just simply not available here, and muriate of potash is only available in minimum quantities of 50kg, which I can't get. Here goes:

Epsom salt and coral chips were suggested as a suitable replacement for dolomite. Arising from this, I have a few queries:

(a) the use of Seachem Equilibrium was discouraged as a replacement for dolomite despite its calcium and magnesium content. The reason for this is the high solubility rate of Seachem Equilibrium as compared to dolomite. However, Epsom salt (MgSO4) is also very soluble. In fact, MgSO4 is one of the main ingredients of Seachem Equilibrium. Hence, why is Epsom salt (MgSO4) a suitable replacement for dolomite despite its solubility, when Seachem Equilibrium is not?

(b) Potassium Sulphate (K2SO4) was discouraged as a replacement for Muriate of Potash (KCl). The reason given was that the SO4 portion of K2SO4 would eventually form hydrogen sulphide, create anaerobic pockets and kill off the plant roots. It was suggested that K2SO4 be mineralized together with the soil in order to get rid of SO4. However, as pointed out above, Epsom salt is a recommended replacement for dolomite. Epsom salt is MgSO4. Why is the sulphate in MgSO4 acceptable, but the sulphate in K2SO4 not acceptable?

Those are the 2 main queries I can think off the top of my head now. It's been bugging me for ages, but on the sticky I've never had a direct answer to my questions. I'm not trying to pick a fight, but those are obvious logic flaws that I notice from the experts and I'm really trying to understand things better, so I hope that someone will be able to clarify and point out where I got it wrong.

Thanks in advance!


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## Philosophos (Mar 1, 2009)

This one has already been answered, actually:
http://www.barrreport.com/co2-aquatic-plant-fertilization/5593-k2so4-reacts-soil.html

Tons of us use MgSO4 and K2SO4, my self included.

I'm not sure why anyone would use CaCO3 in the form of coral chips; it has a miserable bioavailability level, and it will increase your alkalinity. My personal choice for calcium is CaCl2 or CaSO4; each one has its own tricks for proper use, but either are better choices than CaCO3.

-Philosophos


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## Seattle_Aquarist (Mar 7, 2008)

Hi illumnae,

Welcome to APC, I don't think we have chatted in the past! This is a great forum with lots of useful information and friendly people to help when we need it.

Those are a couple of very good questions that you posed. I don't use dolomite, but I do use Epsom salts (MgSO4) and Calcium Chloride (CaCl) to increase water hardness. I also use cuttlebone (85% calcium carbonate). To increase my KH I use baking soda (NaHCO3).

For muriate of potash you might try a garden center, it is a fairly common plant fertilizer.

Seachem has a forum at this website, why not post your question to them concerning the use of Equilibrium?


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## illumnae (Aug 16, 2007)

Thanks so much for the responses Philosophos and Roy. That's 2 more responses than I got over at the other forum! :wink:

Philosophos: Thanks, I didn't think to check BarrReport about this, as my mind was focussed on MTS and APC/TPT are the only 2 forums that came to mind with regard to MTS. As for coral chips, I was only following suggestions for alternatives as advocated in the sticky on TPT. Apparently the dolomite/coral chips are not so much to provide calcium as to keep the soil non-acidic. The theory is that an acidic soil will release heavy metals into the water So anyhow, you're saying K2SO4 and MgSO4 will be safe and will not form hydrogen sulphide pockets under the substrate, since MTS is mineralized and no longer contains organics? If so, then I can simply layer the bottom of the substrate with Seachem Equilibrium. That will provide CaSO4, K2SO4 and MgSO4. I can also be really safe and put a smaller amount of coral chips under the substrate to deal with the alkalinity issue, since Equilibrium is very soluble and may diminish quickly, causing the soil to turn acidic. 

Roy: Thanks for sharing your experience! I can't get muriate of potash here in Singapore. Most garden centres I go to only carry K2SO4, and the only place I found to sell KCl sells it in 50kg bags, which I will not get for obvious reasons 

I didn't try the Seachem forums as I thought this use of Equilibrium is something that is outside of its intended use, much like how they will not say Seachem Flourish Excel is an algaecide, even though many use it as such.


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## Philosophos (Mar 1, 2009)

I don't do mineralized soil my self, so it's not a concern for me. ADA AS has been one of the best things to happen to my tanks.

And ya, that's what Tom appears to have been saying about organics in the substrate. I usually don't just take peoples word on things, but after going through some links he gave me for redox potential, it makes sense to me in a fuzzy kind of way.

Personally I don't bother with equilibrium; I can mix my own for 1/2 the price without buying bulk. You could probably mineralize the soil and cap it with sand for a safe mix though. I'm not sure about putting it underneath, and how well sand will prevent something like unbound ferts.

MS really shouldn't have enough organics to cause problems if it's done properly. I've never seen it mentioned in the guides I've read. If anything, adding CaCO3 is just going to raise your KH and cause stress issues for soft water fish. Then again, I run tanks with <1kH at times without worrying; things seem to hold their own just fine. Seems to work for apisto breeders all over as well.

-Philosophos


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## illumnae (Aug 16, 2007)

Philosophos said:


> I don't do mineralized soil my self, so it's not a concern for me. ADA AS has been one of the best things to happen to my tanks.
> 
> And ya, that's what Tom appears to have been saying about organics in the substrate. I usually don't just take peoples word on things, but after going through some links he gave me for redox potential, it makes sense to me in a fuzzy kind of way.
> 
> ...


Ok thanks so much philosophos  I am not an ADA user generally speaking, except to try it out myself on 1 tank. I don't see very much better growth than other soil substrate brands such as Gex or Magic Soil. Mineralized Topsoil is another "try out" that I'm doing after reading so much hype about it. I'm trying to stick to the "recipe" as much as possible, but due to being in Singapore, I can't get some of the materials. Hence, although some of the recipe (making the soil alkaline) may not make sense to you, I'm trying to emulate anyway.

Hi again by the way, we've chatted briefly before on AquaticQuotient some time back!


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## Philosophos (Mar 1, 2009)

Gex and magic soil aren't something I've seen around or looked into much. I'm not very fond of ADA either, but the substrate is nice stuff.

I forgot that you were from Singapore/AQ, though I did recognize your nic from somewhere. 

Looks like you've got a whole different set of restrictions on your ferts. What all can you get your hands on over there?

Good talking to you again.

-Philosophos


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## illumnae (Aug 16, 2007)

Philosophos said:


> Gex and magic soil aren't something I've seen around or looked into much. I'm not very fond of ADA either, but the substrate is nice stuff.
> 
> I forgot that you were from Singapore/AQ, though I did recognize your nic from somewhere.
> 
> ...


I think due to space constraints, Singapore is generally not too agricultural, and not many are really into gardening. Those that are, due again to space constraints, deal mainly in potted plants. The few who have the cash to buy properties with gardens generally have the cash to hire gardeners to do it for them, and pay for expensive branded chemicals to do what needs to be done. Due to the conditions here, the supply we have available on gardening/landscaping supplies is very different from what's available in say America or Europe.

In the aquatic hobby, KNO3 is banned due to its potential use as a homemade bomb ingredient. We get our other dry ferts (K2SO4, MgSO4, KH2PO4 mainly) from a hydroponics supplier, and the type of stuff available is limited. Many hobbyists tend to use liquid ferts. This is hugely supplemented by the number of people who treat Amano as their idol and being willing to splash (relatively) huge amounts of cash on his range of "coloured water" 

All these factors added together make "DIY" solutions in the hobby a hassle, which makes hobbyists unwilling to take them up, which makes the retailers/importers not willing to carry the products and hence a vicious cycle is maintained.


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