Got a hammer that was perfectly fine earlier this week. Starting from yesterday the upper head has been failing to open, whilst the bottom head looks perfectly ok. Alk is a bit low at 6.4, calcium hovering around 340, and nitrates are the standard somewhere - around - 10. What could be causing this? Can hammers sweeper - tentacle its own colony?
It looks a bit sad cuz I stuck my phone onto it to try and take a photo but it turns out there was a cut on my hand, so I took the photo outside instead.