Sadly to say one of my octos got into the powerhead 2 weeks ago - my fault

. And today despite all the parameters being ideal the second one died for an unknown reason.
However, yesterday evening I noticed a strange behavior of an octopus - he was sticking to a glass in a strange manner, not hiding in the cave as he had usually done at this time of the day.
So, I'am going to send my water for an ICP test to Germany to find if there were any heavy metals (I still had CupriSorb and carbon, but whatever).
The only clue I have is that I was using GFO in a reactor, so probably some part of it may tumbled and released aluminum... As for other reasons I was in the process of changing my salt to tropic marin bioactif, but I don't think it matters.
I'am very upset and eager to find the cause of his death. Now I want to order either 2 blue rings or 2 mimics. But, beforehand I will wait for an ICP test.