# Dual Substrate



## jcinnb (Dec 5, 2010)

I am setting up my first aquarium that will have live plants. What an adventure. I have been reading and researching extensively, but have not been able to reconcile an issue of great import.

I have come away with small gravel for plants, to avoid the compaction that is possible with sand, though there is enough posted on growing plants in sand, that I don't think that is a show stopper.

At the same time, and what appears to be a bit at odds is care of cory cats which I love. I am going to use over 1/2 my "allocation" of fish inches on cories, but I read that sometimes gravel is bad for their "whiskers" and that they greatly prefer sand. However, I see a lot of pictures of cories over gravel...so that may not be a show stopper either.

My current intent is to have about 60% of my tank with small gravel and about 40% with sand. Generally sand would be in the front, and on the discharge end of the tank (no current), with gravel along the back, with a small, narrow patch in the very front for some grass type plants in front. Don't panic, the boundary will be meandering, not stark.

I have not seen this approach mentioned, though my research is a bit short of exhaustive. What am I getting myself into? The only advantage of being on the downhill side of 50 is that I have learned that "you don't know what you don't know." Ideas, comments, solutions are welcome and appreciated.

jcinnb


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## amazon21 (Jun 28, 2010)

I think that would work, another idea is trying a layer of gravel, and on top of that you can put some sand. this way the plants can anchor their roots in the gravel, while the cories have sand for themselves. But many people have put cories in tanks with small gravel. Ask Byron, I believe he has a couple of tanks like this.


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## cbirk (Feb 5, 2010)

The only problem I foresee with this is that over time you will end up with a mix of the two due to tank cleaning, etc. Perhaps find a way to put up some sort of barrier between the sand and gravel, perhaps a small strip of vulcanized rubber. Keeping a layered effect I think would be impossible as sand being smaller would settled below the gravel I would think. just my 2 cents. If your not worried about modifications, perhaps getting some smaller pebbles and some aquarium safe sealant to create a 'wall' to separate gravel and sand?


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## Byron (Mar 7, 2009)

I agree, you will need to divide the sand/gravel areas with a "permanent" type of separator. Rocks would work if they are continuous and probably stuck together with silicone as cbirk mentioned. Otherwise, the two materials will mix. And the suggestion of sand on top of gravel will not work, the sand will immediately work its way down into the gravel. When two sizes of substrate are used, the smaller ends up on the bottom, always.

On the corys, gravel that is not rough/sharp edged will not affect them. I have used small-grain aquarium gravels for 20 years with corys and loaches, and no issues that I could attribute to the gravel. Some gravel is quite sharp edged though, and this must be avoided. Corys do sift through the substrate, that is their nature, and this is attainable with sand or fine gravel.


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## willow (Sep 9, 2006)

my two cents worth because i've done it befor sand and gravel that is 
i made a devider from plastic,and i glued it in place with aquarium silicon,
left it to dry before i began filling,sand at the front, gravel to the back,
i used i think a combination of rocks and wood to hide the devide,
a little did mix,no getting away from it,and when i eventually tired of the way the tank was
i lifted the devide and it all mixed,as Byron rightly said the sand goes to the bottom
as long as you stir,you shouldn't get any black spots.


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## SinCrisis (Aug 7, 2008)

i have 4 types of substrate in my tank, 1mm gravel in front and soil/gravel/flourite in the back. I used a piece of cardboard to get the front to separate from the back and then pulled the board up. I dont plan to gravel vac the back since it is heavily planted and the front, i just be careful about how much of the gravel i stir up and let it settle back slowly. 

It's impossible to get it to not mix on the surface, esp with bottom dwelling fish like cories since they will move the sand around. I have some driftwood and wonder rock to create a natural barrier to keep the blending to a minimum. Underneath, i dont know if they are blending or not but i have yet to see soil or flourite come up during gravel vacs so the blending underneath must be at a minimum


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