Lasb grown plants without water column ferts, CO2 etc

Tom Barr

Staff member
Jan 23, 2005
Here are several plants that I've been growing in outside vaults, (86x24x32) with DI drip water added at 10 gph, this essentially removes any trace of nutrients in the water column thus the weeds can only use the sediment as a nutrient source.

In aquariums, this is rather difficult to measure and set up, but many use slow continuous drip water changers and this might offer a nice method for some. For myself, I am interested in how best to compare a sediment to another.

If there are interactions between sediment A leaching into the water column, this can influence sediment B's growth obviously.

So how to get around this issue?
Scrub the water column using a large DI system.

This forces the plant to use only what it can get from the roots.
The ADA soil does pretty good.

So can you have a nice planted tank without dosing to the water column using a rich sediment? Of course.
Both water column and sediment? Of course.
Water column only? Of course.


I also used another vault and used our ridiculously hard tap well water(GH is 325ppm and 52 mg/L is Mg, very high Mg).

I dripped this through as well at a similar rate.
Not much difference to tell the truth, the color was a bit better in the harder water.


U grammifolia grows like a weed, but the Eusteralis never gets that big, about 40-70% reduction in size in the hard water.
KH is 250ppm.

Isoetes grows well, L aquatic and L aromoatic also do well, as do most all Myrios, Rotala "Green" grows well but slowly.

Here's a nice large giant native pondweed:

Light is about 200 micromoles(about 3w/gal for most folks) and reduced using shade cloth.


In the HC example, think about it, the plant and any plant that can be grown emergent can easily grow without any water column dosing or nutrients over it's entire life other than CO2/O2 etc.
All Crypts and swords obviously can do this, but they can also grow just fine with pure water column dosing as well.

Is this surprising?
No, not one bit.

Plants can grow and get nutrients two different ways.
They can adjust to a variety of nutrient sources, concentrations and conditions.

Tom Barr