[APD] What is "low tech" by todays standards?

["Steve Pushak" <teban at powersonic_bc.ca>]

Robert H asks 'What is "low tech"? I don't think it has anything to do with
the use of garden soil but I think we need to bear in mind that the term
soil applies to almost everything we put in the substrate. I suspect that
folks are using a very wide range of substrates.

I think low-tech really referred to systems without artificial CO2
augmentation. If you use a natural soil, such as you might find in the
garden, and the lighting levels are not excessively bright, you can get very
good growth without CO2 injection, simply availing of the CO2 generated by
the decomposition of the soil. I would greatly recommend peat in this regard
because of its superior stability and low nutrient levels.

Perhaps we might entice Diana Walstad, if she still reads this list, to
offer her own definition of "low-tech"?

In regards to the use of clay in place of soil, I did an experiment a year
ago with clay, sand & peat mixtures. The tank with peat mixtures did much
better than the tank with no peat mixtures. There was not enough P in these
artificial soil mixtures to support lush growth. I did the experiment to
determine the efficacy of peat & to understand some of the effects of using
peat. I also wanted to find out if an artificial mixture of commonly
available materials would be good for aquatic plant growth. Since my growth
rates were poor due to shortages of N & P, I was not able to make any
conclusions about the best mixtures.

For rapid growth, a natural soil with a high mineral content is (and always
has been) the best. For best growth, Barko & Smart found that natural
sediments of 5% organic content had the highest growth rates. Remember that
"rapid growth" is not synonymous with "ease of maintenance". What most
aquarists really want should probably be called "slow sustained growth" with
minimal algae problems!

I don't think "we" use soil (or properly garden soil) because its cheap; I
think we use it because its gives much better results than many artificial
substrate amendments. The chief problem lies in the variability of garden
soils. The better you are at maintaining good growth conditions for the
plants, the easier it will be to use more fertile substrates.

Steve P

P.S. Please remember to trim your posts of extraneous quotes! this promises
to be a lively topic.

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