weeping willow melted away and ideas why?

[ddc0715]

ok I'm going to post this in several places. my 3+ year old whipping willow has melted away .. I started a while back to clean up my water NO3 AND PHOS LEVELS.. performed the following over many many months.

1. lanthanum drips.
2. bi-weekly water changes
3. sand vacuuming.
4. gfo treatments.
5. vinger dosing in my Kalk wasseer. etc

my tank has settled down at NO3-5-10 PHOS.09.. eveyone is clearly alot happier HOWEVER--- AND ---but I have had ONLY ONE casualty. a few weeks back my 3-year-old whipping willow looked as if it was molting( I wrote it off as and adjustment to the cleaner water. but it turns out it has melted away. any theories on why it became unhappy?. all other leathers and softies are just fine. i did find my pencil urchin buried deep into his side one day. and ever since its went downhill. did it eat it or poison the toadstool? this kinda sucks but i got more room now.

 

[vetteguy53081]

GFO is a possibility as would be lack of water flow and high nitrate/phosphate

 

[albano]

Sorry to hear… the good news is that it’s not a weeping willow, based on that first pic.

 

[Grsfish]

I’ve done all those things at some point in my tank and have never had bad reactions to my leather corals. Unless something was done to quickly or too much.?.?.? I wonder if the urchin was eating on there because it wasn’t doing good or if it caused it to do bad. Either way I would probably get sell that urchin in case it has taken a liking to eating corals. My pincushion urchin I have never seen Bother my corals