> I think this is a great idea.
> I don't like using a soil and gravel for my substrate because ev
> pull up a plant, a cloud of murk will come out together with the
> roots, so I prefer a pure fine sand substrate. The problem with
> substrate is that it becomes difficult to feed the root feeding
> can't find pond lily tablets in Singapore). I will try out this
> next chance I get.
> However, I can think of 2 drawbacks of using a slow flow UGF (as
> 1. all substrate MAY become aerobic.
There is not enough water movement for it to become aerobic like a
standard UGF. Water movement is _very_ slow. I find it very hard
to believe that cables moves it much more slowly.
> 2. soil/loam/vermiculite/whatever substrate cannot be used
> because it has a tendency to cloud the water.
You can uses anything you want. I use laterite in all my tanks.
Again, the flow rate is so gentle that it does not move anything
out of the substrate.
> So, instead of placing a UGF plate directly on the tank bottom,
> the UGF plate is placed above a layer of substrate (sand or soil
> method should allow some roots (above the UGF plate)to get warme
> of water borne nutrients, and other roots (under the plate) to g
> anaerobic conditions and if some folks like it, soil/loam/whatev
> course, this would require a kind of UGF equipment that allows
> to reach below them.
Because the water moves so slowly though the substrate, my guess
is the nitrifying bacteria in the first inch or so of substrate
will use most of what ever 02 _is_ drawn in. I can't see any
benefit to having substrate below the filter plate. Some laterite
drops down through the plate just because it is so fine. The
roots quickly find their way down there too.
Your mileage may vary, but I would consider this system past the
experimental stage. Enough people are now using it, and seeing a
difference in their plant growth in long term (1 year +) tanks,
that I would consider the method another viable option.
Aquatic Gardeners Assoc.