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Re: Laterite clay and vermiculite

Jerome <icom at cybl_com> wrote:
>> I went to a local greenhouse, and they could not give me anything of what I 
wanted. (No good peat, no good gravel, etc.) But when I asked for Laterite, they
even knowed the word! I described it as I imagine it, because I never saw it. 
And they showed to me some kind of red clay. Could somebody receive by mail a 
bit of this "laterite" to confirm if it is useful for my tank? <<

This red lateritic clay almost certainly contains a large percentage of iron. It
probably won't be the same texture as Dupla laterite which is somewhat granular 
(George sez) and so if you disturb the substrate by pulling up large rooted 
plants, you may have to contend with very cloudy water (see later comments). I'd
suggest you put it into a bottom layer and then use sand or fine gravel overtop.
You can follow the tried and true Optimum Aquarium method or add some organic 
material into a middle layer. Unfortunately almost all commercial soils contain 
too much organic material and would need to be mixed about 1:10 or 1:20 by 
weight with sand. I don't have any experience yet with peat but I intend to try 
a peat mixture in my next experimental substrate. I think peat will not release 
the large amounts of nitrogen and phosphorus that I got from earthworm castings 
which proved to be quite fertile. I'll be monitoring nitrates and phosphates to 
see how it goes. I'm hoping Neil or someone with practical experience can chip 
in with some advise on the use of peat. Some advise I read about peat suggested 
soaking it or boiling it to remove humic acids. OTOH you may want to retain the 
humic acids for plants like Cryptocorynes and for catfish like Corys, 
Otocinclus, Plecos and for South American tetras like neons and cardinals and 
for many types of killie fish. The only type of peat we seem to be able to get 
in large quantities and at reasonable prices is Canadian Sphagnum Peat Moss and 
this was the type mentioned in the TAG article I mentioned (4:2 or 4:1 I think).

>> Aponogeton Crispus is flowering in my tank. Can I fertilize it by myself 
>from only one flower or should I have more than a flower? <<

Why don't you try it with the single flower if that's all you have and see if 
you can get seeds. If you have other flowers on other plants, you can always use
pollen from them. I think the commercial A crispus is actually a hybrid so 
results may vary in getting it to set seed. Good luck and be sure to advise us 
of your success or otherwise. 

Onis Cogburn <k5vkq at ix_netcom.com> wrote: 
>> My substrate is a variation from the Jim Kelly posting with added 
lauterite and unwashed river sand instead of loam. <<

So you are using vermiculite with sand and laterite? I've used vermiculite 
in two previous substrates. My latest one does not use it and my 
recommendation would be to not use it. It tends to make the substrate quite 
soft and so whenever you uproot a plant, a large clump of 
soil/clay/vermiculite seems to cling to the root ball and create quite a 
cloudy mess. With a clay or soil mixture with sand, the roots seem to come 
out without such a large mess especially if you take your time and do it 
slowly. My personal opinion of vermiculite and other expanded clays like 
kitty litter is that the benefits aren't worth the hassles with this stuff.
>> I change 30% of the water every two weeks and replace it with RO water 
from an under sink unit.  The pH stays at 7, the calcium is 30ppm, 
alkalinity at 100ppm, [snip] I have a little crushed coral in the tank to 
replace the calcium from the water change. <<

I think you should be adding another source of calcium if you are not doing 
so. I don't think coral will supply enough calcium for long term plant 

Steve in Vancouver