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Re: Substrate idea and water quality questions
James Purchase writes:
> The web-site you refer us to appears to be a mini-infomercial for this
> stuff, and should, IMO, be taken with a grain or two of salt (or a few
> of what a lot of hydroponics growers specialize in).<snip>
But I can't find any of this clay for sale on their web-site. Maybe it's
there and I missed it. And what hydroponics growers specialize in is growing
terrestrial plants in an aquatic environment. I still think they must have
something to offer us since we are using the same basic medium.
> Clay in a substrate does help to bind nutrient ions until they can be
> absorbed by plant roots. I don't like the idea of the presence of almost
> aluminum in this stuff - that could present you with toxic conditions once
> submerged. Dupla, in their many writings on laterite, stress the fact that
> laterite is a type of soil which has has most things (which could present
> problems) leached out of it.
But one of the things that is not leached out of laterite, as I understand
it, is the aluminum.
> One possible senario which might prove both interesting and valuable would
> be to set up two tanks, one using Substrate Gold (you said that you've used
> it in the past, maybe you have some left) and a second using this
> pyrophyllite clay. Get a group of plants (hopefully, all from one source)
> and take a representative sample and submit it to a lab for elemental
> analysis (see Steve P.'s web-site for references) and then plant both tanks
> with the rest of the plants. After about six months to a year, take similar
> plant samples from both tanks and submit them for the same analysis to the
> same lab. A comparison of the elements found in each of the samples coupled
> with the growth patterns you observe in the individual tanks could prove
> interesting to a lot of us.
Or maybe I could just grow some plants in the stuff and see how they do. If
I want to get all scientific with it, I'll pop the tuition and go back to
school. I'm trying to have fun here, remember?
> As far as your water quality report, I suspect there might have been a
> mistake made:
> > Silica (as SiO2 ) 42.2 mg/l ; Color (whatever that means) 8.0mg/l
> Are you sure that they report Color using mg/l? Color is usually reported
> T.C.U. (True Color Units). If your municipality is capable of making a
> mistake like this, I'd suspect the rest of the numbers they report as well.
This is a small town, with small town ways. Last year the color was reported
in TCU, but the secretary for the water dept. had a baby. The new secretary
probably got cruising along and didn't notice. I didn't think about it, or I
would have corrected it myself.
> Toronto's water comes in at 1 TCU, and the provincial operational
> for water suppliers calls for this parameter to remain under 5 TCU. But it
> is not a healt related issue, merely aestetic.
> > Now, mind you, some folks on this list keep fish in their tanks for the
> > of providing food for the plants. I, on the other hand am trying to grow
> > plants to keep the nitrates and algae under control, and my fish a Amazon
> > drainage soft-water critters. This means I don't want to get too much Ca
> > Mg or CO3 in my tanks, and I would like to keep conductivity down, which
> > be difficult when providing for the needs of the plants.
> If you are trying to create a blackwater biotope (or even a whitewater
> biotope) as would be found in the Amazon Basin, why not just bite the
> and get yourself a R/O filter. That will strip pretty much everything out
> your source water and allow you to re-create it to match your ideals
> exactly. Much simpler than in trying to deal with what you've got. But
> remember that plants do need both Ca++ and Mg++.
Which is part of the reason I don't want to strip this stuff out. The other
part is that I am renting a very small duplex and sharing it with my four
kids. There really isn't a lot of room for dealing with such a set-up. And
if I can avoid the waste-water issue, all the better. This is the West, not
the Great Lakes Drainage, and water out here is precious.
> In nature, even though the
> water column might be very deficient in these mineral ions, there is so
> water flowing past the plants that they can get enough for their needs. The
> same does not necessarily follow in an aquarium, due to the difference in
> scale. You might have to bump up the Ca++ and Mg++ in your tank in order to
> obtain good plant growth. Many folks on the list report having to use extra
> calcium carbonate to get good plant growth, even in moderately hard water.
> I don't know how many submerged aquatic plants live in the typical
> blackwater biotope in nature.
Precious few, if any. But there are many moving bodies with plants in them.
> Perhaps one of the folks who took the Amazon
> Trip could report (on true aquatics, not on submerged terresterial plants).