RBTA poop or zoo?

[Lobotomy99]

Hi all! I’ve been reading so many different forums and posts regarding BTAs and I’m getting conflicting information.
We purchased a large RBTA with his rock approximately one month ago from a local shop. He was approximately five inches tall and his disc was about 2-3” in diameter.
First photo (blue) shows him when we first put him in our tank. He got some food from when we fed our clowns for a bit and we realized we may have been over feeding him (our clowns haven’t taken to the nem, even now a month later) so we stopped feeding the clowns near the nem (hopefully to get them to realize the nem is their friend!) but we figured the overflow of food from the rest of our tank would be sufficient and to not feed directly.
Every single day he completely deflates (tentacles still look good) into his rock and we thought he was pooping. It is hard brown rocky waste (not wispy) second photo you can see his deflation into the rock, third photo is the “poop”
Can someone clarify what the heck this guy is doing? What we need to do to correct it?
100 gallon tank, 30 gallon sump, Current USA MARINE IC PRO LED lights set to 9 hours of daylight at these settings (w:30, b:75, g:30, r:60) sunrise and sunset (1.5 hours each) at these settings (w:5, b:70, g:20, r:45) moonlight settings are all 0 except blue which is set at 5. ammonia: 0, Trites 0, trates 15, phos .43, calcium 488, magnesium 1410 Alk 8.4 ph 8.4

 

[Clown2020]

Ive only had my nem for around 5 months so don’t claim to be an expert but looks like pooping to me In the third photo.
shrinking smaller at night is normal for mine, I would only be concerned if the tentacles start to deflate and look flat like paper. Mine has just recently split so looks different now but to give you. An idea below is my nem fully out in the afternoon evening and in the early morning before lights on.