So i have some Java Fern Trident that i have had about a month in my heavily planted 55 Gallon tank. And it's now turning black in spots. All of my other 30 varieties of plants are doing fine. Can anyone advise. diy co2 + i use excel. I do a 30 % water change every 5 days due to a heavy fish load. I do ei dosing and my water parameters are fine. I check every 3 days or so. Thanks in advance for any input.