Hydrocoytle japan not doing well maybe

[Sgooosh]

So many yellow leaves the top ones seem to be fine? And some leaves are damaged
Please help this is my favorite plant

 

[Sgooosh]

edges brown....
another forum says it is just diatoms
bottom leaves are rotting yellow

 

[Wills]

What are your lights? Do you know the ratings and how long are they in for?

 

[itiwhetu]

Look at pH and Temperature.