lps die off of 1 head only? any ideas?

[JOEYRM7]

I have a 4 month old system and over the past 4 weeks I have lost only 1 head of an elegance, torch,and frogspawn. The all looked good then the next day one head is retracted and then the next the cleaner shrimp makes sure nothing is left. The other heads are doing fine.

alk 9.o-9.3
cal 465
mag 1325
nitrates 10
ammonia nitrite 0
rodi
15% water change per week
switched to a aquamaxx co-1 skimmer 2 weeks ago

Notice I didn't mention phosphates. I am averaging .15-.2 I don't feed much but its there none the less. I gave up on waiting for my chaeto to do anything and have phosphate reactor coming Thursday.

Can the phosphate be the cause of my problem or something else? I have not found any pests as yet but I keep looking.

Thanks

 

[rogersb]

Whats the flow like ont hose corals? I had an alk issue where I lost some heads recently but I see your alk is fine so flow would be my concern. Those pieces you listed like lower to moderate flow. High flow can rip them from their skeleton. Also, any chance they were near another nasty coral like an acan echinata or galaxia?

 

[JOEYRM7]

I have a 36" tank with about 850gph return plus 2 mp 10's. They do get flow which I though was moderate. The only thing close enough to the frogspawn is another one and the same goes for my 2 torches. The elegance is 2" below an acan and 3" laterally.

 

[JOEYRM7]

They did not look like they were ripped. They would recess in the shell for a day or 2 while the others did just fine and were fully extended. After they recessed a cleaner shrimp went to town on them and gutted the skeleton in no time flat and left the live heads alone.

 

[JOEYRM7]

I also went hunting for pests with a flashlight last night. The only thing I found was a Pavona with bubble algae and 1 small aptasia which I will remove manually later.

 

[JOEYRM7]

Bump

 

[rogersb]

2 mp10's and an 850 return seems overkill if you have them set to ramp to the max. I had 2 mp10's and a 500gph return on a 48" 75g tank and had to watch where I placed LPS. If they are set to ramp to the max try lowering it to halfway and seeing how they react.

 

[JOEYRM7]

Thanks. I have them on reef crest mode already maxxing out at 50%. I have a duncan that in 2 months has added about a half dozen new heads and other hammers, torch's and frogspawn that look great. It's odd that some of them are losing a head. I ordered a phospahte reactor to see if that makes a difference.