Re: soil substrate OR gravel and laterite?

[Roger Miller <rgrmill at rt66_com>]

Rich wrote:

> Reading through some old issues of The Aquatic Gardener, I found lots of
> suggestions to use potting soil covered with a little gravel as a good
> planted aquarium substrate.  On this list and it's archives I haven't
> heard much of that approach, and many books I've looked at have
> suggested gravel & laterite.  Has using a soil substrate gone out of
> fashion, or have people fund that gravel & laterite is better?

So here's a few comments on some available substrates.

Sand and Gravel.  Roundly booed as being too poor to grow plants.  Actually a 
mature (in use for a year or so) sand or gravel substrate grows plants fairly 
well.  Most reported experience suggests that fine sand should be avoided. 

Sand and/or gravel are commonly layered with all of the other materials 
listed below.  Just assume that they are, even if I don't say so.

Soil.  Many different layered variants.  Soil substrates can grow plants 
fairly well but the substrate becomes a mess when plants are moved.  Soil 
substrates almost seem like a cult item, with Diana Walstad serving as High 
Priestess and Steve Pushak as Exhalted Lord.  I'm not current on all that, so 
there may be some other prominent players.  If you're going to do a soil 
substrate right then you need to put on your lab coat and thick glasses and 
study Ms. Walstad's book "Ecology of the Planted Aquarium."

Laterite.  Actually, laterite is a fairly minor additive to a sand or gravel 
substrate.  I think the use of laterite was devised by Dupla and spread by 
their minions.  There may still be some laterite proponents left.  George 
Booth advocated the Dupla method (including laterite) for a long time and I 
think that George and Karla's web site describes their experience in detail.  
The substrate grows plants, but different people report varying experiences 
with ease of use and messiness.   Probably everyone who used too much 
laterite made a mess of their tank.  Generally, hard granular laterite 
products (as I understand the Dupla product to be) are not very messy.  
Powdery or pasty products are reported to cause a lot of problems.

Cat litter.  Yeah, really.  Cat litter seemed to be rather briefly popular 
but I imagine there are still quite a few planted tanks with cat litter 
substrates.  The late Dan Quakenbush was the cat litter sensei.  I'm not sure 
his web site is still active.  Fear not, for Eric Olson has archived plenty 
of discussion about cat litter substrates at The Krib.  Briefly, there is a 
lot of variation in reported experience, depending at least in part on which 
cat litter product is used.  In general you need a hard, non-clumping variety 
with no additives.

Turface and Profile products.  I think these are all similar fired clay 
products.  Dave Gomberg championed the use of Turface which is a product for 
professional grounds keepers.  Profile products (clay soil conditioner, 
aquatic plant soil, maybe a few others) are widely merchandised and available 
at home centers, discount stores and even grocery stores.  These products are 
all reported to grow plants well, but some people criticize their appearance 
and low density.

Seachem substrate products.  Flourite and Onyx are currently popular on APD.  
Flourite comes in several earth tones and Onyx is dark blue-grey.  Both are 
hard and come in coarse sand or gravel grain sizes; both products make 
attractive substrates (at least to some eyes) and both grow plants; both have 
come under fire from some people for being dusty and messy.  Onyx also 
changes the water chemistry, something which Seachem readily admits.  The 
Seachem products are expensive compared to other alternatives.  Shop for the 
best deal.

Other substrates and additives.  I think another manufacturer is entering the 
US market to compete with Seachem.  Was it Coral Sea?  I'm not sure.  ADA 
sells several different substrate materials.  ADA substrates are available in 
Japan and Asia. While other ADA products are sold in Europe and (I think) in 
Canada I'm not sure about the substrates.   ADA products are not readily 
available in the US. There is a gob (glob?) of other substrate additives.  
Most are used like laterite with gravel or in soil.  This would include peat, 
vermiculite, pumice, and pottery clay.  All of these additives have their 
proponents.
  
Substrate debates have raged on APD for years.  The archives are a rich 
source of information, but few people have the time or the skill to mine the 
good stuff.   Thanks to Eric Olson for extracting a lot of the good material 
and organizing it at The Krib where it can be more easily reached.


Roger Miller