Planting Substrate

I am about to set up a 30gal tank and have been having difficulty choosing a suitable substrate.

Initially I thought about a sand base with fine gravel on top, however I am worried that the sand may cause problems if I were to use a gravel cleaner.

I am now considering a double layer of fine gravel with a thin layer of laterite in between. Does this sound like a sensible plan? or would I be best sticking simply to gravel?

Definitely use some kind of substrate fertilizer such as laterite or better yet, flourite.

You shouldn't have any problems using a gravel vac with a sand substrate. Nobody I know who uses sand does. You just don't dig the vac into the sand, just hover over it.

I recommend using sand over gravel, not only do I find it more aesthetically pleasing, but I think it's actually more productive for the plants. Personally I laid a 1inch thick layer of sand, then a bag of flourite ontop, mixed it together, then added a 1 inch thick layer of sand on top. Been working great so far in my tank.

Really it's down to you, and what your budget can afford.

The laterite and gravel sound like a good plan, this is the mix i use, the gravel should be of a fine grade about 1-3mm.

I wouldn't recommend sand if you want a serious planted tank. If you use laterite with sand it will eventually sit on top of the sand which may end up making your water have a red tinge to it constantly. Since switching from sand to gravel/laterite mix my swords have never grown better, my samolus has revived itself and everything is really thriving.

Ive used jbls florapol which you mix into a bottom layer of gravel then top up with plain gravel, its cheap as chips £6.99 here a tub (1 tub does a tank up to 100cm ish)and is suppose to last up to 3 yrs

Layered substrates always sound fine, but in practice, they rarely stay layered for long. The actions of cleaning, fish, snails, plant roots and gravity will churn them up and mix it. Similarly, a fine material over a coarser one will also mix as the fine grains will fall between the larger ones.

I use swimming pool filter sand with some laterite/clay mixed with the lowest 20-30mm. The even grain size and shape prevents a great deal of the packing down problems you get with silver sand or building sand. It still needs to be kept open but a few prods with a chopstick every few weeks is enough.

In the natural state, plants come from fine grained, anærobic, organic rich, (and from personal experience of collecting them - very smelly), muds. Gravel is not terribly similar. It is no suprise to me that my plants grow better on sand than they ever did when I used gravel.

Lateral Line said:

In the natural state, plants come from fine grained, anærobic, organic rich, (and from personal experience of collecting them - very smelly), muds. Gravel is not terribly similar. It is no suprise to me that my plants grow better on sand than they ever did when I used gravel.

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That is interesting LL.

Do you not experience any problems with Hygrogen sulphide in your tanks? I understand the anaerobic environments are necessary in part for a healthy substrate but would have thought with sand the build-up may be excessive in a closed environment like an aquarium. Or does your plant growth, snail population and occasional prodding keep it in check?

Here are my observations on this....

I use a layer of clay & vermiculite followed by a top layer of sand. The only places where the sand tends to get packed is where there are no plants. In other areas it appears that the roots help keep the mix loose.

The occasional prodding with a stick seems to have kept it from developing anaerobic patches.

>>> Do you not experience any problems with Hygrogen sulphide in your tanks?

No.

I am well aware that anærobics in an open system are in fact beneficial because the reducing conditions keep Iron in the ferrous Fe++ state, (green), which is more readily used by plant roots. In oxidising conditions, (ærobic), the Iron looses a further electron and becomes the practically inert ferric Fe+++ ion, (orange-red).

In closed systems, anærobic build ups in the presence of sulphur compounds will allow bacterial chemosynthesis resulting in HS. This is most undesirable in the house, although I suspect small quantities at least, are of no real consequence in the tank.

The action of MTS, plant roots and my chop stick, coupled with the very even grain size and shape of the pool filter sand does not allow it to pack and produce deeply anærobic pockets. I strive to keep the substrate on the edge of anærobic.

When collecting, (SE Asia, Congo Basin, Amazon Basin), the substrate in all but a few cases has been a very fine mud which stirs up into a cloud if you uproot a plant. It is black, full of slowly decaying organics, (leaf litter etc.), and stinks to high heaven, part of the odorous cocktail is HS, but there are other decay products in there as well. The lack of O2 in the soil means the decay rate is slow, so the organics take a while to totally reduce to fine material.

The only place I ever found substantial numbers of plants growing in anything resembling gravel was in the Canima region in the extreme south of Venezuela, near the border with Brazil. There are shallow fast flowing rivers and falls, not rapids as such. Here the current had removed the small silty stuff and left a passable imitation of aquarium gravel. There was an odd plant growing there. Brown and leathery. It looked for all intent and purpose like Fucus serratus or some similar seaweed, but I was 1000km+ from the sea, the water was tea brown with tanins, had a pH of 5.6 no measurable hardness 27C and open to the full tropical sun 12 hours a day. Never did find out what it was.

I did find plants growing in Lake Malawi in sand, but they were few and far between, Potamogeton schweinfurthii, the spotted cichlids in the pic are Fossorochromis rostratus.