# Soil coming up through sand?



## macleod92 (1 Mar 2020)

Hi,


I was wondering if I could get some help with my tank substrate. 

I have put a layer of soil down and then topped it with sand. I did this to give my plants the best nutrients possible to grow growing.


The problem I’m having is that the soil bellow keeps working it’s way up through the sand and making the tank a big mess. 

It seems to be coming up from the base of my plants. 

If I leave it for a few weeks without giving it a proper clean the bottom of the tank will be entirely covered in soil with no sand visible. 


I’ve attached a couple of pictures which show it coming up around the roots of some plants. 

It’s worth baring in mind that this is a couple of days after I gave it a big clean so it’s really not bad at all currently. It has however been a consistent problem since I first got the tank. 


Is there something I’m doing/ have done wrong? Either in the planting or the laying of the substrate?



I’m about to get a new 125l tank and would like to put a nutrient layer under the substrate (planning on using a fine gravel/ corse sand) but don’t want to deal with the constant cleaning. 


Thanks in advance for the help.


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## Matt @ ScapeEasy (1 Mar 2020)

How deep is the sand layer?


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## alto (1 Mar 2020)

Fine sand placed on top of powder aquarium soil works better

You don’t mention what sort of fish or shrimp
Also plant doesn’t seem particularly happy (not that I can see much in the photo aside from many cuts leaf stems, and small leaf number)

You can see Filipe Oliveira uses the La Plata sand over soil (ProdiBio I think) - at present there’s a good amount of soil on the sand, as well as plant bases that are poorly cover covered ... as the carpet plants grow, these gaps will all be obscured and you won’t see the soil/sand mixing in the back right tank corner
Note he won’t add shrimp (especially Amano’s) or substrate active fish (corydoras etc) until plants have established 
And likely will clean up any soil bits on his next visit to AquaFlore 



But when sand and soil are used in the same tank, there will always be extra maintenance needed to keep both looking their best (especially “pristine” sand)


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## macleod92 (1 Mar 2020)

Thanks for getting back to me.



Matt @ ScapeEasy said:


> How deep is the sand layer?



I think the sand layer is about 1.5 inches and the soil is 0.5 - 0.75 inches.



alto said:


> Fine sand placed on top of powder aquarium soil works better
> 
> You don’t mention what sort of fish or shrimp
> Also plant doesn’t seem particularly happy (not that I can see much in the photo aside from many cuts leaf stems, and small leaf number)
> ...





Thanks for posting that video.  In my tank I haven't used (and wasn't planning on for the next tank) using any carpet plants so can't really rely on the carpet filling bits in.  My current setup is basically sand with a log and some rock on top as well as an Amazon Sword, Java fern (and a third plant who's name I can't remember) coming out of the sand.

Again when I left it for about 4 weeks without doing a proper clean I ended up having the entire sand layer covered by a layer of soil to the point that you couldn't see any sand.  Is this what you'd expect when using sand and soil in the same tank?
In terms of fish I have some Guppys and Cardinal Tetras.  I also have two Amano shrimp.

I'm pretty new to all of this so forgive me if this is a stupid question, but could I just get away without using the soil and just use sand?


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## Matt @ ScapeEasy (1 Mar 2020)

It’s certainly not normal but I’m afraid I’m at a bit of a loss... others may be along soon with some more ideas. You could likely get away without the sub layer though swords are more of a root feeder and so would appreciate some root tabs under them at the least. What other plants are you growing?


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## Tim Harrison (1 Mar 2020)

Looks to me as though the sand layer isn't deep enough, at least around the plants. Plus rearranging plants may cause this. 
There is nothing wrong with using soil under sand, it usually works very well, but it's not a system you want to muck around with once planted.
There is only one thing to do and that is to start again, either use an all in one substrate like AS or do the same and use a soil retainer. 
I use this https://www.amazon.co.uk/Grow-Gardman-Greenhouse-Shading-500x60x0-2/dp/B001P3SPIU Details can be found here https://www.ukaps.org/forum/threads/the-soil-substrate-or-dirted-planted-tank-a-how-to-guide.18943/


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## zozo (1 Mar 2020)

That's pretty normal, underwater gravity is different, sand becomes less heavy and kinda liquidizes with all the water molecules in between. Then a course sub-layer contains air/water pockets where the sand slowly seeps into, we could invent a new term for that

What about the "The Hourglass Effect" 

Now plants are not as steady as they seem and they are likely more active down in the substrate than they are above. Roots work their way through the substrate and move it around opening up empty pockets this gives the sand again more opportunity to seep in.

It will keep doing this as long as there are open pockets. As Tim already showed prevention with a mesh in between the substrate layers.
In your case, if you don't like to start over, then wait it out and keep adding sand on top, eventually, all pockets will be filled and sand will no longer sink in. Tho you can't prevent plant roots from pushing some up again.


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## Mr.Shenanagins (1 Mar 2020)

Listen to Tim, a soil retainer does A LOT to keep it down. As long as you sift the soil of large sticks and bark etc, when you place a retainer over it the soil will stay down. I have a tank right now with a retainer over it and one day I accidentally let a power head blow my substrate around exposing the bottom layer with the retainer. No soil came up at all with the exception of some small particles that quickly disappeared. It’s a cheap solution that will save you the headache your dealing with now.


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## macleod92 (1 Mar 2020)

That's all amazing advice.. thank you everyone.  I think I'm going to redo the substrate with a retainer layer and a thicker layer of sand.  Thanks!


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## Barbara Turner (1 Mar 2020)

I just use sand and root tabs and dose daily with EI..

I previously tried with soil and sand, I have a habit of moving stuff arround.. With the soil I had it was like a underwater volcano every time I moved a plant.

I then went to an expensive clay based aquatic soil,this was quite light and my army of Cory's moved it everywhere.  Especially on my white path.

Now I'm just using  at 1.4 to 3mm sand? I'm not sure if it's classed as sand or gravel.. I wanted something course enough to let the water through With root tabs around the plants.
https://www.specialistaggregates.com/sand-water-worn-coarse-p-1241.html


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