Gracilaria dying off.

[DaDom]

Hey, my gracilaria is having an issue where branches turn white, and break off usually just behind the tip. The very tip is usually alive, and it seems to effect longer branches most. This has happened before however there were too many variables for me to know what fixed it that time. It's spreading more than last time and I'm worried I'll lose my plant. Don't have nutrient info aside from knowing that ammonia and nitrites are at zero, while nitrates are approx 20 ppm, and green hair algae and diatoms in the tank both growth at a moderate rate. Source water is the sea and I dumped a little fish food in while cycling initially.

 

[DaDom]

Would like even a short term fix if possible to just keep it alive. Was hard for me to get.

 

[lapin]

It could be some nutrients are lacking. Not sure how often you collect and change sea water in the tank. Also lighting can be an issue. I see you had wanted to use sunlight. Maybe too little or too much.

 

[AlgaeBarn]

What kind of light do you have on it?