11-23-2020, 04:08 PM
Join Date: Apr 2006
| | Re: Stem plants rot
It could be that the substrate is poisoning stem roots with small amounts of H2S. Substrate looks okay but it could be borderline toxic.
In your tank, root area oxygenation by rosette plants is strong enough to protect roots from H2S. However, stem plants are not as vigorous rooters as rosette plants. They also need free CO2, whereas many other plants can get by with bicarbonates as their carbon source. Plants that cannot photosynthesize cannot oxygenate their root area.
Do you have a soil layer? (Soil iron reacts with H2S to neutralize its toxicity.)