My Plants Are Turning Black

[mic8310]

Im a few days into the fishless cycle and the plants i have are turning black (will find out the name if its relevant).
Ive got around 5pmm ammonia and a little nitrite showing. Ive added some mature media so hopefully the cycle should tick over nicely, but what can i do with the plants that are turning black? Is it cos the ammonia is still high? Im using sand, no co2 etc.

cheers

 

[Truck]

how long are your lights on for? and what is water circulation like?

 

[mic8310]

lights were turned off when i went to bed and on again when i woke up but have now decided to leave on to see if the algeeee can grow. Circulation is ok, if i angle the bit sticking out of the filter i can see the sand move at the other side of the tank

 

[Colin_T]

Try to aim the filter outlet towards the water surface. This will maximise the gas exchange and help keep the oxygen levels high in the water. The beneficial filter bacteria like lots of oxygen.

Low light is a common killer of plants. The other option being the wrong type of plants, marsh plants instead of true aquatic plants. Marsh plants will often die when kept underwater. Some true aquatic plants are grown in hydroponic environments and will often shed their old leaves when put in a tank. Then new submersed leaves will grow back in their place.
If you could tell us the plants you have and we can advise whether they are marsh or aquatics.

Just have the lights on during the day and turn them off at night so the plants can get some rest.