Why regular water changes are good for your plants too

[driftw00d]

Got this from Dennerle pamphlet:

"Many plants excrete inhibitors. In nature, these inhibitors are washed away by the flowing water. If no water is changed over a prolonged period, plant growth may start to flag - despite adequate fertilization.

Dennerle thus recommends: Replace 25-50% of the aquarium water with tap water at a temperature corresponding roughly to that of the aquarium water at least once every two weeks.

Don't forget CO2 fertilization - CO2 (carbon dioxide) is the most important plant fertilizer of all!"

[chooz]

The word that Diana Walstad coined in her famous book for this effect is allelo-chemistry or allelopathy.