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Plants and sand

3K views 8 replies 4 participants last post by  Byron 
#1 ·
I'm sorry if I'm reposting something that has probably been answered 100's of times. I looked through the plant forum and didn't see it...so here goes.

What challenges and advantages (if any) or disadvantages would I have doing a planted tank with coarse play sand as a substrate?

Is sand good and acceptable substrate for plants or would I be better off going with eco-complete? Cost is a concern here. Play sand is much cheaper and I would like to be a little thrifty with it if possible.

I have read up on sand in general, and the challenges/differences you face using it as opposed to other substrates, but what I really want to know is the plant aspect.

Some info on the planned setup:

55 gallon aquarium.
Inhabitants: Primarily angelfish, discus. A couple of gouramis.
Hang on back filtration, probably a bio wheel equipped unit.
Plants I want to order: South Central American Plant Habitats Tetra Guppy Angel Hatchetfish Fish Habitats
Planning on using Flourish as a primary fertilizer.
 
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#2 ·
The only thing I could see going wrong would be the sand compacting.
I am pretty sure the plants will be fine. I have sand in my tank, I just need to get some plants. I will also be using seachem flourish. However I have a shoal of cory catfish that root through the sand and stop it from compacting.

What light are you using?
I will let Byron answer the rest, he is a god at this stuff.
 
#3 ·
Although I have never personally used sand [not yet--I have a bag of HD play sand sitting in my fishroom, intended for a future project creating an authentic SA Rio Nego biotope], many on here do and plants grow very well. Every plant authority I have so far come across in my research and monthly magazine articles mentions sand as one substrate but recommends fine grain gravel as the best for plants; the reason is a concern over the compaction than can more easily occur with sand (being finer grain) than gravel. As you are aware of certain aspects of that issue, Herky, I'll confine my comments to how this affects plants.

In nature, the substrate in a watercourse is warmer than the water, by about one degree [Peter Hiscock, Encyclopedia of Aquarium Plants]. This creates a convection current that continually moves water down through the substrate, warming it slightly; the warmer water rises, cooling as it leaves the substrate. The water contains nutrients that the plant roots absorb. There is a complex bacteria cycle occurring in the substrate, both aerobic and anaerobic, in partnership with the plant roots which absorb nutrients, including nitrogen from the anaerobic activity, and in turn release oxygen to feed some of the aerobic bacteria.

This natural convection does not normally occur in an aquarium, so the substrate has to be open enough to allow circulation in order to provide nutrients to the roots. A fine substrate like sand will more easily compact, halting the movement of oxygen and nutrients with the water and creating "dead spots" or anaerobic cnditions. This can cause plant roots to be starved and rot. Ensuring the sand remains free is imortant. The depth of the substrate also enters into this; it must be sufficient to anchor the plants, particularly larger plants like Echinodorus (swords) which have large root systems. But the deeper the substrate, the more likely it will tend to compact. The choice of plants also enters this equation. Plants with large root systems will be much more affected by this that will plants with insignificant or no substrate roots, and these also tend to compact the substrate--just pull up a large established sword plant to see evidence of this.

There are many plants less dependant upon the substrate for nutrients. Stem plants develop roots all along the stems and thus absorb nutrients directly from the water and not via the substrate. Anubias, Java Fern, and floating plants also work this way, since their roots are anchored to objects like wood and rock and not buried in the substrate. Rooted plants like Vallisneria and Sagittaria apparently do well in sand, provided it is not allowed to compact. There is also evidence that plants absorb nutrients through their leaves [see Daina Walstad, Ecology of the Planted Aquarium].

Several on this forum use sand in planted aquaria, so they will have the best advice as to how the above issues are handled.

Byron.
 
#4 ·
Awesome, Byron. You are a treasure trove of valuable knowledge as always. I think I am going to try out a sand setup. You only live once...might as well try new things. I just wonder what kind of implements one would use to agitate sand and reduce the effects of compaction. Some kind of little sand rake, or fork like object with tines to penetrate in and agitate the sand...interesting stuff. I've also read on another site that putting a layer of peat down before placing substrate is a good idea...but I wonder on the merits of that.
 
#5 ·
I know this sounds strange but after trying many different things to "stir" my sand (fork, chop stick, knitting needle, etc.) my favorite thing to use is now a pair of bacon tongs. Weird, I know, but it works for me.
 
#8 ·
It was by accident that I discovered that it works very well. I was experimenting to see how well they'd work for the planting of stem plants. They didn't work well for that but by shoving the tongs all the way down into the sand and scissoring them back & forth I found that it really mixed up the sand well while leaving the sand relatively "flat". I like my substrate to remain fairly even and chopsticks and such left big swirls that I would then have to go back over by hand to smooth out.
They sell tongs & other types of cleaning and planting equipment on-line but my bacon tongs are alot cheaper than those items. :)
 
#9 ·
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