New member with some frogspawn confusion

[Nyk Reed]

I am a new member that joined at the coral expo. I teach at Trevecca Nazarene University and have a student maintained 55 gallon tank in one of the Biology labs. The tank has been running for 2 years. The inventory is kenya tree, leptoseris, Alveopora, zoos, Cyphastrea, frogspawn, and 2 clownfish. There is a refugium with chaeto and a carbon reactor. The frogspawn had been doing well until one of the heads lost its tentacles overnight a month ago. We couldn't figure out the issue. The head with the missing tentacles is still growing buds. This morning, the remaining head is missing half its tentacles. There did appear to be a copepod in the middle of the frogspawn this morning. This coral has been in the tank for atleast 6 months. We haven't been able to diagnose the issue. The perplexing part is that the frogspawn that first lost tentacles has growing buds. Any ideas would be appreciated.
Parameters
Salinity 35ppm
Temp 78
Alk 9
Calc 390

 

[Ty Hamatake]

What's the flow like where the frogspawn is? I really have no idea what it could be, I'm just here because I'm curious too

 

[Nyk Reed]

It's at the bottom of the tank with medium flow. When healthy there was a slow sway of the tentacles.

 

[pickupman66]

So the copepod is there just cleaning up the rotting tissue. I cannot pinpoint what it was on this instance, but where does the rest of your parameters read out? also, what sort of lighting are you running on the tank?

 

[H@rry]

Are the clowns irritating it?

 

[Nyk Reed]

Running current Usa orbit leds. It is possible that the clowns are irritating it. I have not seen the clowns mess with the frogspawn but have no clue if it is happening at night. The frogspawn was a single headed frag when purchased and grew nicely until recently. That's been part of the difficulty of diagnosing this classroom tank's issues. The phosphate measures close to zero based on the API colorimetric test. The ph is 7.9. We have been doing 5 gallon water changes every Friday. Writing this made me realize that we haven't tested for nitrate or nitrite recently.

 

[Nyk Reed]

Ok. I may have figured it out. I mentioned earlier that this is a student maintained tank in one of the labs. We have a weekly rotation for tank cleaning and water changes amongst myself and students. I noticed that the frogspawn has lost heads after one individuals last two water changes in the rotation. I talked to them and In addition to vacuuming the bed to remove detritus, the frogspawn was held up to the powerhead to remove any detritus from it. I think this is the problem because the tentacles started going the next day and all other corals seem fine. I told them that they had the right idea but were just being a little heavy handed.