I've used feather caulerpa for years with no ill effects. I have had it "go sexual" before, where it basically melts.Once it occurred because of too much light. I had always heard and read caulerpa needs a lot of light, even up to 24 hours a day. That is how I started using it and it started melting a few months in. I dialed the light back to 20 hours a day and have had no similar incidents again.The only other time it happened to me was earlier this year. We had our kitchen cabinets painted and I believe the VOC in the paint caused the pH in my tank to plummet and this caused the caulerpa to melt - in addition to killing both shrimp and a few fish.In neither case did the melting caulerpa cause any issue with my system. I siphoned out all the yellow, melting caulerpa I could and ran carbon in the system for a few days until all yellowing in the water went away. I also grow chaeto in my sump. I'd be happy to give you some of either kind, or both, to try out.