# Laterite and dolomite usage



## Krunal (Jan 12, 2019)

Hello everyone,

I am newbie to planted tanks and walstad method. I want to setup tank using walstad method. While researching about substrate I got to know about using laterite and dolomite. I have some questions about these and processing soil. Please help. More suggestions and tips are welcome.

1) Safe laterite and dolomite- what should be percentages of metals etc. in laterite and dolomite to be safe for plants and livestock? 
I think presence of some metals will be toxic. What should be it's components and in what ratio?

2) Can I use laterite as top layer? Small rocks as decoration instead layer? What about dolomite?

3) is mineralization of soil necessary? I am adding 20% organic fertilizer and 80% soil. 

4) Should I mix sand with soil for aeration?

5) how much of laterite and dolomite i should use?


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## hoppycalif (Apr 7, 2005)

Have you read Diana Walstad's book? I would strongly recommend reading it before going ahead with the aquarium. It isn't very expensive, if you have a Kindle or other book reader, but it is loaded with good information.

Dolomite is a source of calcium and magnesium, in a form that very slowly releases them into the water. Laterite is a depleted form of clay, good for slowly adding iron to the substrate. Neither one should have any harmful minerals in it. Laterite is not a good top layer. Dolomite can be used in place of sand/gravel, but it will continually add calcium and magnesium, making your water hard. That can limit the plants and fish that would do well with it. Mineralization is a method for converting ammonia based nitrogen in the soil to nitrate based nitrogen. It isn't essential in a regular aquarium, and isn't advisable in a El Natural aquarium. 20% organic fertilizer can be deadly, depending on exactly what you are using.

Reading that El Natural forum will help you a lot, but reading the book will help a lot more.


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## Michael (Jul 20, 2010)

1. Dolomite and laterite sold for horticultural use should be safe.

2. Some forms of laterite are hard enough to use as a cap if the particles are the right size, about 2 to 3 mm. Don't use dolomite for a cap unless you want to drastically raise the pH of the water as required by certain types of fish.

3. Mineralization is helpful but not necessary. I don't think you should use the organic fertilizer. It may make the substrate too fertile, leading to ammonia and algae problems.

4. Not necessary. Sand doesn't help with aeration or oxygen content in submerged soils.

5. If your soil is highly organic (all ingredients were once living materials), you can use up to 50% laterite or much less. Dolomite is used primarily to raise pH. If your soil and water have low pH you can use more dolomite. But in any case you don't need much--5% of total soil volume would be plenty.

I think you are more concerned about all of this than you need to be. Many different types of soil will work well in a Walstad tank. The most common mistake is to use soils that are too fertile, having added manure or artificial fertilizers.

Good luck and keep us updated.


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## Krunal (Jan 12, 2019)

Thank you very much Michel and hoppycalif. I have also started a thread 'choosing soil' about options of substrates available in India. I will update there for you guys. Thanks again.


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## tiger15 (Apr 9, 2017)

All my tanks have dolomite gravel substrate which is calcium magnesium carbonate. It only raises gH and kH slightly as dolomite is much less soluble than limestone. With dolomite, you will never need to dose gH. Laterite is iron rich clay, yet the iron is not bioavailable, so your plants can still show iron deficiency unless you dose chelated iron in the water column.


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## VTChemical (10 mo ago)

Hello, I'm from Vietnam. Dolomite is a mineral that contains both calcium and magnesium, it is often used for the purpose of increasing the pH of water and adding Ca+ and mg+ in the water. Currently on the market are selling this type in the form of fine powder
You can see more at this article: Vai trò và cách sử dụng bột dolomite trong ngành thủy sản - Hoá chất VT
We supply vietnamese dolomite powder: Vôi Dolomite Dùng Trong Thủy Sản - Hoá chất VT


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