Soil in pots

KB Koh and I have been discussing the possibility of using pots to
provide a rich substrate for certain plants such as Ludwigia glandulosa
in aquaria which have only gravel or gravel with laterite. A point
that Neil Frank mentioned was that when you have a soil substrate
(or perhaps just a thick layer of mulm), the idea is not to disturb
that too much since it would cause water to mix with it and provide
enough nutrients that might cause an algae bloom. This situation 
would be exacerbated when you had high lighting intensity. I recently
had a minor green algae bloom in a similar situation.

I recall that Karen Randall frequently uses pots with potting soil
and micronized iron for Crypts; presumably the lighting is not so
strong. If we were using a 50:50 mix of soil and composted manure,
and putting it in pots with a layer of gravel on the surface, would
there be a danger of triggering an algae problem after putting it
in the water? Has anybody tried this?

I guess one way to minimize this problem would be to ensure a
healthy covering of Salvinia (or similar floating plant) and other
plants which are rapid growers to help soak up the excess nutrient
spike (like Myriophylum).


PS. Anybody in Vancouver or Canada, I have excess Salvinia minima,
Myriophylum aquatica, Ludwigia arcuata, H difformis, rooted Water
Sprite (Ceratopteris pteroides? with the highly branching leaves)
At times I also have extra Bacopa, H. poly, Valisneria, sword plants
and Hydrocotyle leucocephala (Pennywort).  I might part with snippets 
of the red Ludwigia sp. and Lobelia cardinalis; hope to have lots
more of this later.