Adding sand to gravel substrate...

I have a gravel substrate and under gravel filtration along with built in sponge filtration. I also like having cory but only have one. I would like to add some more cory but would want the proper surface for them to dig and forage. My problem is that, using under gravel filtration, sand would just sift through the existing gravel and wipe out the under gravel filtration.

While doing other searches I've come across fine mesh material that is supposed to alleviate this potential issue. From the little I've looked this material would prevent the sand from sifting through the gravel base. If anyone knows the material to which I refer, could I remove all bottom decorations and lay this material over the gravel base and then add sand? If the little I've read is true, and I understand correctly, I'd add something like a half inch of black sand which would give a decent base for the corys and, also, add to the under gravel filtration by giving a finer filter media.

As a side question can you add different types of cory and still have them happy or do you need all to be of the same type?

jaylach said:

As a side question can you add different types of cory and still have them happy or do you need all to be of the same type?

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All same type is best.

connorlindeman said:

All same type is best.

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OK, I can understand that. Still, the one cory that I have is an albino. Is an albino a specific type or can any cory be such? Actually a group of albinos would probably be pretty cool on black sand if I can do the sand.

I use undergravel filtration, and if I were going to put in sand for my cories I would put it in a container of some type, they used to make these rock like reptile feeding dishes that were pretty cool. But the gravel I use is pretty fine and smooth and it hasn't bothered my corydoras in the past. I had a group of bronze corydoras breeding in an undergravel filtered tank for several years. The babies hid in the fallen leaves under the anubias.

The thing with corys is that they are natural community fish that enjoy company. They will tend to shoal/accompany other cory species as do my own.

Alice B said:

I use undergravel filtration, and if I were going to put in sand for my cories I would put it in a container of some type, they used to make these rock like reptile feeding dishes that were pretty cool. But the gravel I use is pretty fine and smooth and it hasn't bothered my corydoras in the past. I had a group of bronze corydoras breeding in an undergravel filtered tank for several years. The babies hid in the fallen leaves under the anubias.

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Thanks but, if I added sand, I prefer to not use containers that would obstruct the under gravel filtration. While not what I'd probably buy the following is along the lines of what I would put between the gravel and sand. It would allow water flow but not allow the sand to sift through the gravel. By the way my gravel is 'tumbled' such as is done to rough polish rocks in lapidary. There should be no sharp edges.

Lynnzer said:

The thing with corys is that they are natural community fish that enjoy company. They will tend to shoal/accompany other cory species as do my own.

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HAVE YOU VOTED YET​

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Thanks for the info. That is good news to hear. While albinos would probably look good on black sand, if I can do as said just above, a bit of variety would be nice.

Just had a thought... Sigh, it is usually dangerous when I think and gives me head aches...

With my black table and black frame on my tank adding a layer of black sand would sort of give the whole thing a sort of goth appearance especially since the fake tree trunk is largely dark. Except for the albino cory the current population tends to be on the dark side being a dark pleco and black skirts.

While I don't do goth as to my personal appearance the goth look intrigues me me a LOT. Adding a half inch or so of black sand over the current brown/orange gravel would greatly add to the goth aspect... The balance given by the green plants would keep it from being too dark but it could still look goth.

I THINK that I MAY be finally finding the direction I want for my tank's appearance. Am I wrong in thinking a half inch of black sand over the current gravel would give a strong goth appearance? Might even remove some of the current gravel and do more black sand although the tank could use a deeper substrate as it is currently a probable average depth of 2 inches when it should me a minimum of three.... Ah, the current is probable more like 2.5 inches but still thin.

Still I need to know if my idea as to using filter fabric to keep the sand from sifting through the gravel would likely work before I can do any of this... LOL! I very much hope for positive responses as I am VERY excited about the direction I want to go but need honest answers even if it kills what I want to do.

jaylach said:

Still, the one cory that I have is an albino. Is an albino a specific type or can any cory be such?

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There are a few species of cory which have albino variants. If you could find out which species you have, you could get more non-albinos of the same species.
If you post a photo of your albino cory, one of our cory experts should be able to tell you which species it is.

In general, cories can be mixed but it is best to have at least 4 of each species in the mix.

Your gravel is quite thick so this could work out well given your under gravel filtration situation

Get a 2 litre plastic bottle...if an ex fizzy drink bottle, wash out very thoroughly....cut the bottom off the bottle to make a funnel (no need to buy a funnel when you can easily DIY one). Turn the bottle upside down, use the topless neck to gently move the gravel to make a smallish "bowl shaped" beach space - without exposing the bottom/filtration, leaving a good half inch of gravel in place - then using the bottle, still upturned, very slowly and gently pour the sand through the bottle, holding the neck no more than an inch above the gravel area that you have "bowl shaped", move the bottle very very slowly til the bowled out area is filled, then chuck the bottle into the recycling bin, you have a nice sandy beach for the Cories and it has not disturbed the filtration system underneath.

I have a feeling that your water clarity issue that you have been fighting is potentially due to the under gravel filtration system since when used on relatively small or contricted footprint aquariums, such as cubes, any fine detritus does not disperse and becomes contricted by virtue of size and shape of the aquarium that it is used in and thus becomes aethetically visible compared to the larger volume/footprint aquariums where it can "spread out" and not be so obvious. If you were to change to a standard internal or external filter, your view would not be so obscured given the size and shape of your aquarium.

The problem with filter floss is that it tears and makes a mess if it gets disturbed. Sponge with a fine hole size will end up stuffed full of sand too, so you'll lose the ability for under filter development of beneficial bacteria.
You need something that will be thin and with a mesh size that'll prevent escape of sand through it to the bottom layer.
Perhaps a bit of lace curtain cut to size.

wasmewasntit said:

Your gravel is quite thick so this could work out well given your under gravel filtration situation

Get a 2 litre plastic bottle...if an ex fizzy drink bottle, wash out very thoroughly....cut the bottom off the bottle to make a funnel (no need to buy a funnel when you can easily DIY one). Turn the bottle upside down, use the topless neck to gently move the gravel to make a smallish "bowl shaped" beach space - without exposing the bottom/filtration, leaving a good half inch of gravel in place - then using the bottle, still upturned, very slowly and gently pour the sand through the bottle, holding the neck no more than an inch above the gravel area that you have "bowl shaped", move the bottle very very slowly til the bowled out area is filled, then chuck the bottle into the recycling bin, you have a nice sandy beach for the Cories and it has not disturbed the filtration system underneath.

I have a feeling that your water clarity issue that you have been fighting is potentially due to the under gravel filtration system since when used on relatively small or contricted footprint aquariums, such as cubes, any fine detritus does not disperse and becomes contricted by virtue of size and shape of the aquarium that it is used in and thus becomes aethetically visible compared to the larger volume/footprint aquariums where it can "spread out" and not be so obvious. If you were to change to a standard internal or external filter, your view would not be so obscured given the size and shape of your aquarium.

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Actually I think my haze in the tank is actually over oxidization. I mean I can see free floating tiny air bubbles floating around which will be apparent in following images of my cory.

Lynnzer said:

The problem with filter floss is that it tears and makes a mess if it gets disturbed. Sponge with a fine hole size will end up stuffed full of sand too, so you'll lose the ability for under filter development of beneficial bacteria.
You need something that will be thin and with a mesh size that'll prevent escape of sand through it to the bottom layer.
Perhaps a bit of lace curtain cut to size.

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Just to continue my tendency of odd thoughts... How about cutting up some nylon panty hose to separate the sand and gravel? It should last just about forever and would be easily kept clear with regular suction vacuums of the substrate which I would do anyway...

OK, here is the little beasty cory. It is really small as can be seen in the image that also holds a black skirt. Hard to get a really good shot tonight as little beasty is very active tonight and all over the tank.

Again all the white dots are free floating minute air bubbles. I'm still looking for some reliable air flow valves as the air flow is obviously too high. I don't understand why such air valves are so hard to find. I want two valves each having one input and two outputs. I want dual outputs so I can adjust the actual air flow to the risers by 'bleeding' air through the second output to avoid straining the Whisper 40 air pumps by restricting the air flow. I have a Whisper 40 attached to each riser. Ya, I know that I could do both risers with one Whisper 40 in a 20 gallon cube but, just like with my computers, I believe in backups. If a Whisper dies I still have the other. This attitude is also why my pumps and heater are on a battery backup. Just seems to me to be better to over protect than regret that I did not.

What is the footprint of your aquarium?

It looks far too constricted for undergravel filtration....there is nowhere for any excess air or detritus to dispel or disperse properly. I am not sure that cutting back on airflow is ever going to cure the issue, there is no room for dispersal in a cube compared to a rectangle or other larger, more open shaped aquarium, a cube is too restrictive so the air bubbles or whatever it is simply cannot shink down or spread out enough to become invisible to you.

Under gravel filtration is very tetchy and does not suit all aquarium shapes or sizes. I understand the desire to have the clutter free aquarium but certain shapes and volumes are just not suitable for under gravel by virtue of the lack of elbow room for dispersal

You can't mix sand and gravel together because the sand falls between the gaps in the gravel and you have sand under the gravel.

You can't use sand with undergravel filters because the sand blocks up the slits in the filter plates and stops it working. That's why they are called undergravel filters and not undersand filters.

If you want sand in the tank for the Corydoras, use a plastic container to hold the sand and put the container in the gravel. Have the edge of the container about 1/2 inch above the surrounding gravel.

The plastic container will probably reduce the effectiveness of the undergravel filter because the aquarium is small.

wasmewasntit said:

What is the footprint of your aquarium?

It looks far too constricted for undergravel filtration....there is nowhere for any excess air or detritus to dispel or disperse properly. I am not sure that cutting back on airflow is ever going to cure the issue, there is no room for dispersal in a cube compared to a rectangle or other larger, more open shaped aquarium, a cube is too restrictive so the air bubbles or whatever it is simply cannot shink down or spread out enough to become invisible to you.

Under gravel filtration is very tetchy and does not suit all aquarium shapes or sizes. I understand the desire to have the clutter free aquarium but certain shapes and volumes are just not suitable for under gravel by virtue of the lack of elbow room for dispersal

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What do you mean by footprint? I figure that you mean tank dimensions so that info follows.

Width is 16 inches.
Depth is 18 inches.
Height is 18 inches.
Actually, by the above numbers, the cube MAY actually be 25 gallon, not 20.

I don't really get your saying that the tank is too restrictive for under gravel filtration. Under gravel is controlled by substrate depth and air flow through the risers. My free floating bubbles are not caused by restriction ( in my humble opinion). The bubbles are are caused by each of the two risers being driven by Whisper 40 pumps running wide open due to not being able to find decent valves. By specs I'm driving enough air through the risers to drive an 80-100 gallon tank.

It also must be added that I am also using a sponge built in filter with ceramics for bacteria. While it has space for carbon packs I am not using. The built in system is pushing 93 GPH which equates to about 4 water cycles per hour. Between the built in and under gravel I can't see any lack of filtration.

The tank is healthy with a PH of in the area of 6.0-6.2. Ammonia is like 0.025PPM with Nitrites showing 0.0. I have not done a recent nitrate test. The tank is actually pretty clear with just the little minute free floating air bubbles. If nothing else the dark color of the black skirt in an above image shows healthy conditions.

While I have had a long spell without a tank I know under gravel filtration from long ago when that was all there was.

Going back to my actual question... Can I put a barrier, such as nylon panty hose as I mentioned earlier, between the sand and gravel to prevent sifting of the sand through the gravel base while still keeping things easy to clean?

The tank is healthy and, if I could find decent valves to cut down the air flow, would probably be crystal clear. While I initially had issues with the health of the tank all is now good. This is not about tank health but appearance. There are really just two issues...
1) Would panty hose work as a barrier between sand and gravel.
2) Where the *&^%%& can I find decent brass or stainless one input and two output air valves?

jaylach said:

What do you mean by footprint? I figure that you mean tank dimensions so that info follows.

Width is 16 inches.
Depth is 18 inches.
Height is 18 inches.
Actually, by the above numbers, the cube MAY actually be 25 gallon, not 20.

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The footprint is surface area (length x width)

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jaylach said:

1) Would panty hose work as a barrier between sand and gravel.

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not very well. just stay with gravel or get a small power filter, let it establish, then remove the undergravel filter and change the gravel to sand

jaylach said:

2) Where the *&^%%& can I find decent brass or stainless one input and two output air valves?

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eBay or ask your pet shop to order some in.

The plastic T-pieces and taps work fine and are cheaper.