Water Column Dosing


Lifetime Charter Member
Lifetime Member
Jan 24, 2005
In another thread Tom linked to a paper that compared the root growth of several aquatic plants in situations where there was or was not competition from other plants. In the former case root growth seemed more vigorous. The link is at http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=164724

As one who has gradually and grudgingly come to accept water column dosing as a valuable tool in aquatic plant culturing, this upsets me a little. It seems to be suggest that the plants in question are looking to the substrate for their nutrients.

So, my questions:

1. Would the behavior or the plants have been different if the water columns had contained the proper nutrients? (I assume that they did not.)

2. In an aquarium with a gravel substrate (no substrate nutrients) with adequate water column dosing, would the mass of the roots be less than that of plants in an aquarium with a nutrient-rich substrate, also with adequate water column dosing? (This is another way of saying, "Which environment do the plants really prefer?")

3. Are there some plants that just do better with a nutrient-rich substrate?(Observation: My Cryptocoryne beckettii grow to a height of 12 to 15 inches in a soil-based tank, with long stems. The same plant, in a gravel tank with water column dosing, looks like a bush, with many leaves in a small area, about 7 inches tall. Part of a Seachem plant tab was placed beneath it when it was planted.)

The above questions assume that the aquarium is not stocked heavily with fish.

Thanks in advance.