Plants turning black

[Cichlidboy]

What is causing all my under water plants to turn black.

 

[Marck]

Is the same pattern appearing simultaneously on different species?

 

[Cichlidboy]

Is the same pattern appearing simultaneously on different species?

Yes

 

[Marck]

Is this in the heated pond?
Has temperature or another water quality variable changed due to weather or season?
Which species are turning black?

 

[Cichlidboy]

Is the same pattern appearing simultaneously on different species

Is this in the heated pond?
Has temperature or another water quality variable changed due to weather or season?
Which species are turning black?

Yes in heated pond and I did have a ph spike but it's under control now amazon sword , Java fern and anubus

 

[Marck]

Is the leaf tissue itself turning black, or is it coated with a dark substance, possibly cyanobacteria (blue-green algae)?

 

[Cichlidboy]

Is the leaf tissue itself turning black, or is it coated with a dark substance, possibly cyanobacteria (blue-green algae)?

It is covered with the algae I just removed some

 

[Marck]

That's relatively good news. The plants aren't dying form some type of blight.
Check the nitrate/ammonia levels. That pH spike may also have had something to do with it.